Pub Date : 2025-02-19DOI: 10.1016/j.ijft.2025.101141
Fadi Alnaimat , Ahmad Rahhal , Bobby Mathew , Abdallah Berrouk
This research evaluates heat transfer and pumping power associated with heat sinks having straight microchannels with triangular ribs on sidewalls using Ansys Workbench. The performance of the heat sinks is evaluated in terms of thermal resistance, pumping power, and a figure of merit (FOM). The heat sink with triangular ribs exhibits lower thermal resistance and higher pumping power than the straight MCHS. In addition, this study evaluates the influence of geometric parameters of the ribs on thermal resistance and pumping power. This study finds that increasing rib dimensions reduces thermal resistance by ∼ 57% while increasing pumping power; however, the FOM improves with reduction in dimensions of the ribs. Reducing the pitch of the fins reduces thermal resistance by ∼ 71% along with increase in the pumping power. Reducing microchannel spacing lowers thermal resistance by ∼68% without affecting pumping power, leading to improved FOM. The reduction in the dimensions of the microchannels improved thermal resistance by ∼ 52% while increasing pumping power; the FOM of MCHSs increased with an increase in channel dimensions.
{"title":"Fluid flow and heat transfer investigation of microchannel heat sink with sidewall triangle ribs","authors":"Fadi Alnaimat , Ahmad Rahhal , Bobby Mathew , Abdallah Berrouk","doi":"10.1016/j.ijft.2025.101141","DOIUrl":"10.1016/j.ijft.2025.101141","url":null,"abstract":"<div><div>This research evaluates heat transfer and pumping power associated with heat sinks having straight microchannels with triangular ribs on sidewalls using Ansys Workbench. The performance of the heat sinks is evaluated in terms of thermal resistance, pumping power, and a figure of merit (FOM). The heat sink with triangular ribs exhibits lower thermal resistance and higher pumping power than the straight MCHS. In addition, this study evaluates the influence of geometric parameters of the ribs on thermal resistance and pumping power. This study finds that increasing rib dimensions reduces thermal resistance by ∼ 57% while increasing pumping power; however, the FOM improves with reduction in dimensions of the ribs. Reducing the pitch of the fins reduces thermal resistance by ∼ 71% along with increase in the pumping power. Reducing microchannel spacing lowers thermal resistance by ∼68% without affecting pumping power, leading to improved FOM. The reduction in the dimensions of the microchannels improved thermal resistance by ∼ 52% while increasing pumping power; the FOM of MCHSs increased with an increase in channel dimensions.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101141"},"PeriodicalIF":0.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The need to minimise metal degradation and dissolution in biodiesel (BD) fuels used in the transportation sector is nowadays becoming a challenging task that, if not properly attended to, can lead to human safety issues, environmental concerns, and vehicular failures in automobile systems. Metal degradation by BD fuel is a major issue of great concern to the scientific community, and this has resulted in intense research globally. Sustainable use of waste cooking oil (WCO) BD (WCOBD), which has a lower carbon footprint, and its implication on corrosion degradation in the transportation industry in terms of detailed applications of UV–Vis, FTIR, and SEM techniques to elucidate the corrosion behaviour of metallic components in the BD at various durations (0, 28, 42, and 56 days), temperature (25 °C), and atmospheric pressure (760 mmHg) are investigated in this study. The fuel properties of the produced WCOBD were within acceptable standard limits: viscosity of 4.785 mm2/s; density of 0.886 g/cm3; acid value of 0.120; flash point of 172.4 °C; fire point of 136 °C; cloud point of -4.2 °C; and pour point of -7.8 °C. The major fatty acid group responsible for the metal degradation was C18, with a high degree of unsaturation, having 90.63 % of the total constituent of the BD. UV–Vis analysis after the various immersion periods revealed two peaks at wavelengths of 928.3 and 1033.76 nm, which were formed during the esterification and transesterification reactions of the free fatty acid from the WCO and thus responsible for the metal degradation at the various immersion periods. FTIR spectra exhibited characteristics of double peaks around 2918 and 2842 cm-1 wavelengths, with other peaks equally observed as being present in the BD. These peaks represented CO, CO, CH, CC, and (CH2)n functional groups as expected from free fatty acids in BD. SEM morphology revealed randomly distributed uneven structures, which were attributed to the formation of protective corrosion products and their physical adsorption on the metal surface. Thus, this study contributes to a deeper understanding of the corrosiveness of WCOBD to carbon steel, elucidates techniques to ascertain the degree and form of corrosion on the metal surface during storage and transportation of the BD in vehicular systems, and reveals the potential inherent in the use of un-inhibited WCOBD in real-world automotive applications.
{"title":"Implications of waste cooking oil biodiesel on carbon steel alloy in automobiles: Corrosion degradation","authors":"Kenneth Kennedy Adama , Kingsley Eghonghon Ukhurebor , Uyiosa Osagie Aigbe , Ismail Hossain","doi":"10.1016/j.ijft.2025.101143","DOIUrl":"10.1016/j.ijft.2025.101143","url":null,"abstract":"<div><div>The need to minimise metal degradation and dissolution in biodiesel (BD) fuels used in the transportation sector is nowadays becoming a challenging task that, if not properly attended to, can lead to human safety issues, environmental concerns, and vehicular failures in automobile systems. Metal degradation by BD fuel is a major issue of great concern to the scientific community, and this has resulted in intense research globally. Sustainable use of waste cooking oil (WCO) BD (WCOBD), which has a lower carbon footprint, and its implication on corrosion degradation in the transportation industry in terms of detailed applications of UV–Vis, FTIR, and SEM techniques to elucidate the corrosion behaviour of metallic components in the BD at various durations (0, 28, 42, and 56 days), temperature (25 °C), and atmospheric pressure (760 mmHg) are investigated in this study. The fuel properties of the produced WCOBD were within acceptable standard limits: viscosity of 4.785 mm<sup>2</sup>/s; density of 0.886 g/cm<sup>3</sup>; acid value of 0.120; flash point of 172.4 °C; fire point of 136 °C; cloud point of -4.2 °C; and pour point of -7.8 °C. The major fatty acid group responsible for the metal degradation was C18, with a high degree of unsaturation, having 90.63 % of the total constituent of the BD. UV–Vis analysis after the various immersion periods revealed two peaks at wavelengths of 928.3 and 1033.76 nm, which were formed during the esterification and transesterification reactions of the free fatty acid from the WCO and thus responsible for the metal degradation at the various immersion periods. FTIR spectra exhibited characteristics of double peaks around 2918 and 2842 cm<sup>-1</sup> wavelengths, with other peaks equally observed as being present in the BD. These peaks represented C<img>O, C<img>O, C<img>H, C<img>C, and (CH<sub>2</sub>)<sub>n</sub> functional groups as expected from free fatty acids in BD. SEM morphology revealed randomly distributed uneven structures, which were attributed to the formation of protective corrosion products and their physical adsorption on the metal surface. Thus, this study contributes to a deeper understanding of the corrosiveness of WCOBD to carbon steel, elucidates techniques to ascertain the degree and form of corrosion on the metal surface during storage and transportation of the BD in vehicular systems, and reveals the potential inherent in the use of un-inhibited WCOBD in real-world automotive applications.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101143"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-18DOI: 10.1016/j.ijft.2025.101142
Sonam Darjay , Ephraim Bonah Agyekum
In recent time, Bhutan as a small landlocked nation between China in the north and India in the south started to experience a gap in hydro electricity supply and demand. To address the growing electricity demand in the country, solar energy can be a diversification of Bhutan's renewable energy to address domestic energy security and global environmental concerns. In this paper, efforts have been made to assess the future energy potential from the rooftop solar photovoltaic (PV) systems in Thimphu City. For this study, we designed and simulated a 12 kWp grid-tied solar PV systems using PVSYST software. The result showed the annual solar energy generation, final energy yield and performance ratio (PR) of 19,336 kWh, 4.63 kWh/kWp and 84 % respectively. The estimated final energy yield and PR aligned with findings from countries like Saudi Arabia, India, and Pakistan, highlighting the strong solar energy potential in Thimphu. In addition, we conducted simple scenario analysis for energy generation potential when PV systems are installed on 90 %, 75 %, and 50 % of the available building rooftops in Thimphu City. The additional annual solar energy injected into the grid during lean hydropower generation periods was 61 GWh, 51 GWh, and 34 GWh for the three scenarios, respectively. Furthermore, the projected annual cost savings on electricity imports from additional energy generation from grid-tied rooftop solar PV systems was $3.23 million, $2.70 million, and $1.80 million across the three scenarios, using import price figure of 2023. Additionally, installing 12 kWp PV systems on 50 % of building rooftops in Thimphu City alone could result in environmental cost savings of $1.91 million during periods of low hydropower generation. The study is expected to benefit the government agencies, other institutions and individuals interested in solar energy generation using solar PV technology.
{"title":"Assessment of solar energy generation potential in Western Bhutan – A case study of 12 kWp grid-tied rooftop solar photovoltaic system","authors":"Sonam Darjay , Ephraim Bonah Agyekum","doi":"10.1016/j.ijft.2025.101142","DOIUrl":"10.1016/j.ijft.2025.101142","url":null,"abstract":"<div><div>In recent time, Bhutan as a small landlocked nation between China in the north and India in the south started to experience a gap in hydro electricity supply and demand. To address the growing electricity demand in the country, solar energy can be a diversification of Bhutan's renewable energy to address domestic energy security and global environmental concerns. In this paper, efforts have been made to assess the future energy potential from the rooftop solar photovoltaic (PV) systems in Thimphu City. For this study, we designed and simulated a 12 kWp grid-tied solar PV systems using PVSYST software. The result showed the annual solar energy generation, final energy yield and performance ratio (PR) of 19,336 kWh, 4.63 kWh/kWp and 84 % respectively. The estimated final energy yield and PR aligned with findings from countries like Saudi Arabia, India, and Pakistan, highlighting the strong solar energy potential in Thimphu. In addition, we conducted simple scenario analysis for energy generation potential when PV systems are installed on 90 %, 75 %, and 50 % of the available building rooftops in Thimphu City. The additional annual solar energy injected into the grid during lean hydropower generation periods was 61 GWh, 51 GWh, and 34 GWh for the three scenarios, respectively. Furthermore, the projected annual cost savings on electricity imports from additional energy generation from grid-tied rooftop solar PV systems was $3.23 million, $2.70 million, and $1.80 million across the three scenarios, using import price figure of 2023. Additionally, installing 12 kWp PV systems on 50 % of building rooftops in Thimphu City alone could result in environmental cost savings of $1.91 million during periods of low hydropower generation. The study is expected to benefit the government agencies, other institutions and individuals interested in solar energy generation using solar PV technology.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101142"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This research investigates the intricate thermal dynamics of Maxwellian nanofluids interacting with a sloping, porous, and heat-conductive melting surface under the influence of magnetic fields. The thermal and hydrodynamic behavior of Maxwellian nanofluids plays a significant role in optimizing heat transfer applications in engineering and industrial processes. This study aims to examine the influence of buoyancy, bioconvection on the Falkner-Skan flow of Maxwellian nanofluids over a sloping, melting surface. The analysis assumes a porous and thermally conductive wedge surface subjected to a stable magnetic field and incorporates the effects of Brownian motion, thermophoresis, and gyrotactic microorganisms. To simplify the governing equations, similarity transformations are applied, converting the partial differential equations into a set of ordinary differential equations. The resulting equations are solved numerically using MATLAB's robust bvp4c solver, ensuring validation through comparison with existing literature. The study reveals that parameters such as the magnetic field strength, Deborah number, and melting surface characteristics significantly enhance flow behavior and boundary layer thickness, whereas parameters like Prandtl number and thermophoresis diminish temperature profiles. The findings underscore the critical interplay between magnetic and thermal parameters, providing insights for improving heat management in advanced technological systems. These results have practical implications for designing efficient thermal systems in industries ranging from chemical engineering to bio-nanomaterial production.
{"title":"Buoyancy effects on falkner-skan maxwellian nanofluid flow with bioconvection over a melting wedge","authors":"Rakesh Choudhary , Amit Parmar , Pramod Kumar , Qasem Al-Mdallal","doi":"10.1016/j.ijft.2025.101136","DOIUrl":"10.1016/j.ijft.2025.101136","url":null,"abstract":"<div><div>This research investigates the intricate thermal dynamics of Maxwellian nanofluids interacting with a sloping, porous, and heat-conductive melting surface under the influence of magnetic fields. The thermal and hydrodynamic behavior of Maxwellian nanofluids plays a significant role in optimizing heat transfer applications in engineering and industrial processes. This study aims to examine the influence of buoyancy, bioconvection on the Falkner-Skan flow of Maxwellian nanofluids over a sloping, melting surface. The analysis assumes a porous and thermally conductive wedge surface subjected to a stable magnetic field and incorporates the effects of Brownian motion, thermophoresis, and gyrotactic microorganisms. To simplify the governing equations, similarity transformations are applied, converting the partial differential equations into a set of ordinary differential equations. The resulting equations are solved numerically using MATLAB's robust bvp4c solver, ensuring validation through comparison with existing literature. The study reveals that parameters such as the magnetic field strength, Deborah number, and melting surface characteristics significantly enhance flow behavior and boundary layer thickness, whereas parameters like Prandtl number and thermophoresis diminish temperature profiles. The findings underscore the critical interplay between magnetic and thermal parameters, providing insights for improving heat management in advanced technological systems. These results have practical implications for designing efficient thermal systems in industries ranging from chemical engineering to bio-nanomaterial production.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101136"},"PeriodicalIF":0.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-14DOI: 10.1016/j.ijft.2025.101139
Dheyaa J. Jasim , Mustafa Habeeb Chyad , Laith S. Sabri , Soheil Salahshour , Omid Ali Akbari , M. Hekmatifar
In this research, the CFD simulation of the respiratory tract was discussed. Limited research was conducted in the field of respiratory systems to examine the respiratory system as a true model for various input structures in inhalation and exhalation, although numerous studies were conducted by researchers. This study aimed to develop a dependable method for obtaining the true respiratory system geometry from a 24-year-old man's CT scan data and preparing it for input into CFD software. this research performs a numerical analysis of the airflow from the nasal inlet in both the inhalation and exhalation modes, using a turbulent airflow mode with a flow rate of 60 liters per minute. The effect of different inputs on the airflow in the human respiratory system is simulated for flat, pipe, and semi-spherical cross sections using CFD for turbulent flow. The results show that the velocity increased as air entered the nasopharynx. In flat, pipe, and semisphere modes, the velocity increased from 2.8 m/s, 2.07 m/s, and 4.14 m/s to 7.41 m/s, 5.48 m/s, and 8.40 m/s, respectively. The Dynamic pressure drop coefficient)Cp(in flat, pipe, and semisphere modes decreased from 79.38, 34.24, and 69.57 to 32.84, 17.13, and 31.44, respectively. The velocity in flat, pipe, and semisphere modes decreased from 7.46 m/s, 4.45 m/s, and 10.29 m/s to 1.54 m/s, 0.96 m/s, and 2.70 m/s, respectively. In the flat and pipe modes, the Cp increased from 17.17, -5.46, to 34.01, and 29.75, respectively. Velocity increased as air entered the larynx. Numerically, the velocity in flat, pipe, and semisphere modes increased from 5.00 m/s, 2.78 m/s, and 7.35 m/s to 9.06 m/s, 6.56 m/s, and 9.79 m/s, respectively. The Cp increased in pipe and semisphere modes. Velocity decreases as the air enters the trachea. Numerically, the velocity in flat, pipe, and semisphere modes decreased from 6.69 m/s, 4.86 m/s, and 7.16 m/s to 3.44 m/s, 3.44 m/s, and 3.90 m/s, respectively. The Cp in the pipe and semisphere modes decreased from 0.77, and -1.59 to -7.33, and -11.51, respectively.
{"title":"Simulation of the turbulent air flow of inhalation and exhalation in the respiratory system using computational fluid dynamics","authors":"Dheyaa J. Jasim , Mustafa Habeeb Chyad , Laith S. Sabri , Soheil Salahshour , Omid Ali Akbari , M. Hekmatifar","doi":"10.1016/j.ijft.2025.101139","DOIUrl":"10.1016/j.ijft.2025.101139","url":null,"abstract":"<div><div>In this research, the CFD simulation of the respiratory tract was discussed. Limited research was conducted in the field of respiratory systems to examine the respiratory system as a true model for various input structures in inhalation and exhalation, although numerous studies were conducted by researchers. This study aimed to develop a dependable method for obtaining the true respiratory system geometry from a 24-year-old man's CT scan data and preparing it for input into CFD software. this research performs a numerical analysis of the airflow from the nasal inlet in both the inhalation and exhalation modes, using a turbulent airflow mode with a flow rate of 60 liters per minute. The effect of different inputs on the airflow in the human respiratory system is simulated for flat, pipe, and semi-spherical cross sections using CFD for turbulent flow. The results show that the velocity increased as air entered the nasopharynx. In flat, pipe, and semisphere modes, the velocity increased from 2.8 m/s, 2.07 m/s, and 4.14 m/s to 7.41 m/s, 5.48 m/s, and 8.40 m/s, respectively. The Dynamic pressure drop coefficient)C<sub>p</sub>(in flat, pipe, and semisphere modes decreased from 79.38, 34.24, and 69.57 to 32.84, 17.13, and 31.44, respectively. The velocity in flat, pipe, and semisphere modes decreased from 7.46 m/s, 4.45 m/s, and 10.29 m/s to 1.54 m/s, 0.96 m/s, and 2.70 m/s, respectively. In the flat and pipe modes, the Cp increased from 17.17, -5.46, to 34.01, and 29.75, respectively. Velocity increased as air entered the larynx. Numerically, the velocity in flat, pipe, and semisphere modes increased from 5.00 m/s, 2.78 m/s, and 7.35 m/s to 9.06 m/s, 6.56 m/s, and 9.79 m/s, respectively. The C<sub>p</sub> increased in pipe and semisphere modes. Velocity decreases as the air enters the trachea. Numerically, the velocity in flat, pipe, and semisphere modes decreased from 6.69 m/s, 4.86 m/s, and 7.16 m/s to 3.44 m/s, 3.44 m/s, and 3.90 m/s, respectively. The C<sub>p</sub> in the pipe and semisphere modes decreased from 0.77, and -1.59 to -7.33, and -11.51, respectively.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101139"},"PeriodicalIF":0.0,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-14DOI: 10.1016/j.ijft.2025.101132
Carlo Carotenuto , Federico Ferrari , Stefano Salerno , Federico Bernabei , Wassim Lababidi , Luca Montorsi , Massimo Milani
Dialysis machines are vital devices for individuals with chronic kidney diseases, functioning as artificial kidneys to purify blood by removing waste and excess fluid. At the core of these machines are volumetric pumps, with peristaltic pumps being particularly essential for their high precision and gentle handling of sterile fluids such as blood.
This study focuses on the experimental characterization of a four-roller peristaltic pump with a neoprene tube, analyzing its volumetric efficiency under varying suction (Pin) and discharge (Pout) pressures, motor speeds (rpm), and at a constant temperature (35 °C). A lumped-parameter model was subsequently developed to replicate the pump's real behavior using Siemens’ Amesim software.
The pump was modeled with four isolated pumping volumes, assuming complete occlusion of the tube by the rollers. The deformability of the neoprene tube was incorporated using a generalized tubing law, treating it as a linearly elastic material.
Experimental results showed that due to neoprene's high deformability, the pump's flow rate depended significantly on Pin. Variations in suction pressure altered the tube's expansion and contraction, affecting the volume of liquid between rollers. Conversely, the flow rate showed minimal dependence on Pout. These trends were also validated through the lumped-parameter model, with simulated data aligning within the experimental volumetric efficiency's mean ± one standard deviation for all tested conditions.
This study provides a simplified but accurate and validated model for peristaltic pumps, which provides the total flow processed by the pump, the flow and pressure ripples and the pressure trend within the pumping volume.
{"title":"Lumped parameter modeling and experimental characterization of pressure effects in a roller-type peristaltic pump with neoprene tubing for dialysis machines.","authors":"Carlo Carotenuto , Federico Ferrari , Stefano Salerno , Federico Bernabei , Wassim Lababidi , Luca Montorsi , Massimo Milani","doi":"10.1016/j.ijft.2025.101132","DOIUrl":"10.1016/j.ijft.2025.101132","url":null,"abstract":"<div><div>Dialysis machines are vital devices for individuals with chronic kidney diseases, functioning as artificial kidneys to purify blood by removing waste and excess fluid. At the core of these machines are volumetric pumps, with peristaltic pumps being particularly essential for their high precision and gentle handling of sterile fluids such as blood.</div><div>This study focuses on the experimental characterization of a four-roller peristaltic pump with a neoprene tube, analyzing its volumetric efficiency under varying suction (Pin) and discharge (Pout) pressures, motor speeds (rpm), and at a constant temperature (35 °C). A lumped-parameter model was subsequently developed to replicate the pump's real behavior using Siemens’ Amesim software.</div><div>The pump was modeled with four isolated pumping volumes, assuming complete occlusion of the tube by the rollers. The deformability of the neoprene tube was incorporated using a generalized tubing law, treating it as a linearly elastic material.</div><div>Experimental results showed that due to neoprene's high deformability, the pump's flow rate depended significantly on Pin. Variations in suction pressure altered the tube's expansion and contraction, affecting the volume of liquid between rollers. Conversely, the flow rate showed minimal dependence on Pout. These trends were also validated through the lumped-parameter model, with simulated data aligning within the experimental volumetric efficiency's mean ± one standard deviation for all tested conditions.</div><div>This study provides a simplified but accurate and validated model for peristaltic pumps, which provides the total flow processed by the pump, the flow and pressure ripples and the pressure trend within the pumping volume.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101132"},"PeriodicalIF":0.0,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-13DOI: 10.1016/j.ijft.2025.101137
Andrea Montalti, Alessandro Ghini, Gian Maria Santi, Alfredo Liverani
This study investigates an innovative surface finishing process for 3D-printed components using Material Extrusion (MEX). By applying controlled heating to the outer layer with a heated, semi-spherical tip, surface quality can be enhanced without adding material, effectively reducing imperfections caused by nozzle deposition. Using a prototype tool with distinct thermal properties, simulations were conducted to assess the optimal process parameters, including tool temperature, movement speed, and depth of influence within the material. Thermal simulations of the tool were performed to analyse temperature distribution and efficiency, identifying potential heat losses. Additionally, interactions between the tool tip and the material were simulated, highlighting temperature distribution at various depths. The simulations reliably model the tool's performance, providing a solid foundation for precise process parameter calibration while minimising reliance on experimental testing. Analyses conducted on PLA, PETG, ABS, PEEK, and PEKK demonstrated a clear correlation between speed and temperature in achieving optimal results. For materials with a high glass transition temperature, either a lower speed or a higher tool temperature is required, depending on the material's thermal properties.
{"title":"Thermal simulation for enhanced control in innovative ironing processes on 3D-printed components","authors":"Andrea Montalti, Alessandro Ghini, Gian Maria Santi, Alfredo Liverani","doi":"10.1016/j.ijft.2025.101137","DOIUrl":"10.1016/j.ijft.2025.101137","url":null,"abstract":"<div><div>This study investigates an innovative surface finishing process for 3D-printed components using Material Extrusion (MEX). By applying controlled heating to the outer layer with a heated, semi-spherical tip, surface quality can be enhanced without adding material, effectively reducing imperfections caused by nozzle deposition. Using a prototype tool with distinct thermal properties, simulations were conducted to assess the optimal process parameters, including tool temperature, movement speed, and depth of influence within the material. Thermal simulations of the tool were performed to analyse temperature distribution and efficiency, identifying potential heat losses. Additionally, interactions between the tool tip and the material were simulated, highlighting temperature distribution at various depths. The simulations reliably model the tool's performance, providing a solid foundation for precise process parameter calibration while minimising reliance on experimental testing. Analyses conducted on PLA, PETG, ABS, PEEK, and PEKK demonstrated a clear correlation between speed and temperature in achieving optimal results. For materials with a high glass transition temperature, either a lower speed or a higher tool temperature is required, depending on the material's thermal properties.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101137"},"PeriodicalIF":0.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-13DOI: 10.1016/j.ijft.2025.101135
Firas Ghanim , Ali Hasan Ali , Ghassan Ezzulddin Arif , Ali Raza
The article covers two other sources of solar energy: industrial devices and nanofluids, which are employed in thermal engineering. The article makes the case that thermal engineering and industrial solar energy technologies can generate solar energy from alternative sources, such as nanofluids. Fractal fractional derivatives are a new and modified type of fractional derivative that has been developed to solve issues with hybrid nanofluid suspension. Several numerical techniques, such as Stehfest's and Tzou's algorithms, and the integral transform method, also known as Laplace transformation, are used to examine the approximate solution of the governed PDEs. At various time values, the numerical impacts of heat and flow rate are discernible. We then deduced that the momentum and heat profiles decreased with increasing fractal limitations. Furthermore, the momentum and temperature gradients progressively rise close to the plate and fall away from it when all prerequisites are satisfied. Because of the physical relevance of the nanoparticles under consideration, the water-based (H2O) solution also has a more obvious influence when comparing various nanofluids than the (CMC)-based hybrid nanofluid.
{"title":"Fractional analysis for heat consumption of CuO-based hybrid nanofluid via integral transform","authors":"Firas Ghanim , Ali Hasan Ali , Ghassan Ezzulddin Arif , Ali Raza","doi":"10.1016/j.ijft.2025.101135","DOIUrl":"10.1016/j.ijft.2025.101135","url":null,"abstract":"<div><div>The article covers two other sources of solar energy: industrial devices and nanofluids, which are employed in thermal engineering. The article makes the case that thermal engineering and industrial solar energy technologies can generate solar energy from alternative sources, such as nanofluids. Fractal fractional derivatives are a new and modified type of fractional derivative that has been developed to solve issues with hybrid nanofluid suspension. Several numerical techniques, such as Stehfest's and Tzou's algorithms, and the integral transform method, also known as Laplace transformation, are used to examine the approximate solution of the governed PDEs. At various time values, the numerical impacts of heat and flow rate are discernible. We then deduced that the momentum and heat profiles decreased with increasing fractal limitations. Furthermore, the momentum and temperature gradients progressively rise close to the plate and fall away from it when all prerequisites are satisfied. Because of the physical relevance of the nanoparticles under consideration, the water-based (<em>H</em><sub>2</sub>O) solution also has a more obvious influence when comparing various nanofluids than the (<em>CMC</em>)-based hybrid nanofluid.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101135"},"PeriodicalIF":0.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Combustion-driven thermoelectric and thermophotovoltaic power systems taking advantage of meso‑ and micro-scale combustors, that are direct energy conversion modules, have attracted growing interest. So, in this research, three double annulus axial swirlers are implemented to investigate the effect of swirl direction of the fuel and air flows with respect to each other on thermal performance and combustion characteristics of a non-premixed meso‑scale combustor. This study comprehensively evaluates several key performance metrics of the meso‑combustor, including its operational envelope, flame characteristics, exhaust gas temperature, mean outer wall temperature and its uniformity, pollutant emissions, wall heat losses, and thermal efficiency. It is found that adding swirl to the co-axial airflow significantly enhances the operational envelope, expanding it by >600 % in comparison to zero-swirl airflow configuration. Co-rotating swirling flows is reported to have a more positive influence on flame blow-out than counter-rotating swirling flows. Furthermore, the flame lift-off height decreases with an increase in airflow rate for a set fuel flow rate, with the lift-off heights in the co-swirl configuration demonstrating the least sensitivity to increases in fuel flow rate. Analysis of the combustion products reveals that CO concentration has a U-shaped dependency of the equivalence ratio, where the co-swirl mode exhibits lower CO concentrations by approximately 31 % compared to the counter-swirl mode. Additionally, the co-swirl mode displays the superior values of exhaust gas temperature (∼ 3.3 %), combustion efficiency (∼ 34 %), mean outer wall temperature (4.6 %), radiation efficiency (∼ 15 %), and thermal efficiency (∼ 3.5 %) compared with counter-swirl mode under identical operating conditions.
{"title":"Thermal and combustion performance of a swirl-stabilized meso-combustor for micro-power generation","authors":"Soroush Sheykhbaglou, Amirreza Ghahremani, Sadegh Tabejamaat","doi":"10.1016/j.ijft.2025.101133","DOIUrl":"10.1016/j.ijft.2025.101133","url":null,"abstract":"<div><div>Combustion-driven thermoelectric and thermophotovoltaic power systems taking advantage of meso‑ and micro-scale combustors, that are direct energy conversion modules, have attracted growing interest. So, in this research, three double annulus axial swirlers are implemented to investigate the effect of swirl direction of the fuel and air flows with respect to each other on thermal performance and combustion characteristics of a non-premixed meso‑scale combustor. This study comprehensively evaluates several key performance metrics of the meso‑combustor, including its operational envelope, flame characteristics, exhaust gas temperature, mean outer wall temperature and its uniformity, pollutant emissions, wall heat losses, and thermal efficiency. It is found that adding swirl to the co-axial airflow significantly enhances the operational envelope, expanding it by >600 % in comparison to zero-swirl airflow configuration. Co-rotating swirling flows is reported to have a more positive influence on flame blow-out than counter-rotating swirling flows. Furthermore, the flame lift-off height decreases with an increase in airflow rate for a set fuel flow rate, with the lift-off heights in the co-swirl configuration demonstrating the least sensitivity to increases in fuel flow rate. Analysis of the combustion products reveals that CO concentration has a U-shaped dependency of the equivalence ratio, where the co-swirl mode exhibits lower CO concentrations by approximately 31 % compared to the counter-swirl mode. Additionally, the co-swirl mode displays the superior values of exhaust gas temperature (∼ 3.3 %), combustion efficiency (∼ 34 %), mean outer wall temperature (4.6 %), radiation efficiency (∼ 15 %), and thermal efficiency (∼ 3.5 %) compared with counter-swirl mode under identical operating conditions.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101133"},"PeriodicalIF":0.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-12DOI: 10.1016/j.ijft.2025.101134
Melika Mohammadi, Ali Ahmadpour, Seyed Amin Chabok
Rotary viscous micropumps, recognized as a prevalent mechanism in microfluidics systems, have recently been introduced to transport non-Newtonian fluids, especially yield-stress fluids. However, conventional single-rotor viscous micropumps often lack efficiency and effectiveness when dealing with these particular fluid types. To address this challenge, the present study explores the use of dual-rotor viscous micropumps for transporting Bingham fluids and their associated performance enhancement for the first time. In a four-step approach, the effects of geometrical and operational parameters, including diameter ratio, distance ratio, rotational velocity ratio, and height ratio on two performance metrics, flow rate, and efficiency, are analyzed, and optimal values are recorded. Enhanced designs, optimized for maximum flow rate and efficiency, are evaluated at four distinct Bingham numbers (Bn), with comparative performance assessments against single-rotor micropumps. The working fluid is simulated using the Herschel-Bulkley model to capture its non-Newtonian behavior, with velocity and viscosity contours providing insights into flow characteristics. Numerical findings reveal significant performance improvements with dual-rotor micropumps, achieving a maximum enhancement rate of 12 while Bn = 2 compared to single-rotor configurations. Additionally, the adverse effects of yield stress on both efficiency and flow rate are substantially mitigated, particularly for high-viscosity fluids, due to a reduction in blocking vortex structures. These findings highlight the potential of dual-rotor viscous micropumps as an effective solution for transporting yield-stress fluids.
{"title":"Performance enhancement of double-rotor viscous micropump for transporting Bingham fluid","authors":"Melika Mohammadi, Ali Ahmadpour, Seyed Amin Chabok","doi":"10.1016/j.ijft.2025.101134","DOIUrl":"10.1016/j.ijft.2025.101134","url":null,"abstract":"<div><div>Rotary viscous micropumps, recognized as a prevalent mechanism in microfluidics systems, have recently been introduced to transport non-Newtonian fluids, especially yield-stress fluids. However, conventional single-rotor viscous micropumps often lack efficiency and effectiveness when dealing with these particular fluid types. To address this challenge, the present study explores the use of dual-rotor viscous micropumps for transporting Bingham fluids and their associated performance enhancement for the first time. In a four-step approach, the effects of geometrical and operational parameters, including diameter ratio, distance ratio, rotational velocity ratio, and height ratio on two performance metrics, flow rate, and efficiency, are analyzed, and optimal values are recorded. Enhanced designs, optimized for maximum flow rate and efficiency, are evaluated at four distinct Bingham numbers (Bn), with comparative performance assessments against single-rotor micropumps. The working fluid is simulated using the Herschel-Bulkley model to capture its non-Newtonian behavior, with velocity and viscosity contours providing insights into flow characteristics. Numerical findings reveal significant performance improvements with dual-rotor micropumps, achieving a maximum enhancement rate of 12 while Bn = 2 compared to single-rotor configurations. Additionally, the adverse effects of yield stress on both efficiency and flow rate are substantially mitigated, particularly for high-viscosity fluids, due to a reduction in blocking vortex structures. These findings highlight the potential of dual-rotor viscous micropumps as an effective solution for transporting yield-stress fluids.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101134"},"PeriodicalIF":0.0,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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