Pub Date : 2024-10-05DOI: 10.1016/j.csite.2024.105248
The current article studies the improvement of the discharging rate in cold storage systems by modifying the tank configuration and incorporating additives. Specifically, the study inspects how varying the diameter (dp) and fraction (ϕ) of nano-powders affects the process duration. The governing equations, derived under the assumption of negligible slip velocity of nanoparticles and convection terms, were solved using the Galerkin method. The computational grid was modified owing to location of the ice front, and unsteady terms were discretized using an unconditionally stable approach. The results indicate that initially, increasing dp decreases the process duration by approximately 20.01 %, but further increases in dp lead to a 49.53 % rise in the duration. As the process time increases, the amount of ice produced also increases, with nanoparticle loading resulting in a significantly higher ice yield. Specifically, the incorporation of nanoparticles enhances the storage rate by approximately 41.37 %.
{"title":"Simulation of solidification for saving energy with using nanomaterial involving conduction heat transfer","authors":"","doi":"10.1016/j.csite.2024.105248","DOIUrl":"10.1016/j.csite.2024.105248","url":null,"abstract":"<div><div>The current article studies the improvement of the discharging rate in cold storage systems by modifying the tank configuration and incorporating additives. Specifically, the study inspects how varying the diameter (dp) and fraction (ϕ) of nano-powders affects the process duration. The governing equations, derived under the assumption of negligible slip velocity of nanoparticles and convection terms, were solved using the Galerkin method. The computational grid was modified owing to location of the ice front, and unsteady terms were discretized using an unconditionally stable approach. The results indicate that initially, increasing dp decreases the process duration by approximately 20.01 %, but further increases in dp lead to a 49.53 % rise in the duration. As the process time increases, the amount of ice produced also increases, with nanoparticle loading resulting in a significantly higher ice yield. Specifically, the incorporation of nanoparticles enhances the storage rate by approximately 41.37 %.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142442660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.csite.2024.105249
Calotropis gigantea, commonly known as Indian milkweed, is a prevalent plant in Asia. It typically thrives in open and unused areas, often considered a weed. This plant produces flowers and fruits consistently throughout the year, exhibiting a continuous flowering and fruiting cycle. This research investigated the viability of Calotropis gigantea seed oil as a potential source intended for biodiesel manufacturing. The oil was obtained from Calotropis gigantea seeds using hexane extraction in the Soxhlet apparatus. The seeds were determined to contain 33.3 wt% of oil content. The process of biodiesel production involved conducting a transesterification reaction. Further, the produced biodiesel was blended with pure diesel and three different nanoparticles, Titanium dioxide (TiO2), Chromium oxide (Cr2O3), and Silicon dioxide (SiO2), to evaluate combustion performance, and emission characteristics of a single-cylinder diesel engine under various load conditions. Incorporating Cr2O3 nanoparticles into the CGSB20 biodiesel blend yielded significant improvements in BTE, coupled with BSFC reduction. Specifically, in the CGSB20 + Cr2O3 fuel mixture, BTE increased notably by 31.2 %, reaching a value of 0.33 g/kWh for BSFC. Similarly, for the CGSB20 + SiO2 and CGSB20 + TiO2 blends, BTE experienced enhancements of 29.2 % and 28.1 %, respectively, while BSFC values were lowered to 0.37 and 0.4 g/kWh. Furthermore, the unchanging dispersal of nanoparticles within the CGSB20 blend exhibited extraordinary cylinder pressure and HRR values, reaching 77 bar and 34.2 J/CA, respectively. The CGSB20+ Cr2O3 blend yielded favorable emissions outcomes. Specifically, CO, NOx, UHC, and smoke emissions were approximately 4.5 g/kWh, 725 ppm, 0.11 g/kWh, and 23.6 %, respectively.
{"title":"Impacts of novel calotropis gigantea seed biodiesel usage as a fuel substitute along with various metal-oxide nanoparticles on the DICI engine characteristics","authors":"","doi":"10.1016/j.csite.2024.105249","DOIUrl":"10.1016/j.csite.2024.105249","url":null,"abstract":"<div><div>Calotropis gigantea, commonly known as Indian milkweed, is a prevalent plant in Asia. It typically thrives in open and unused areas, often considered a weed. This plant produces flowers and fruits consistently throughout the year, exhibiting a continuous flowering and fruiting cycle. This research investigated the viability of Calotropis gigantea seed oil as a potential source intended for biodiesel manufacturing. The oil was obtained from Calotropis gigantea seeds using hexane extraction in the Soxhlet apparatus. The seeds were determined to contain 33.3 wt% of oil content. The process of biodiesel production involved conducting a transesterification reaction. Further, the produced biodiesel was blended with pure diesel and three different nanoparticles, Titanium dioxide (TiO<sub>2</sub>), Chromium oxide (Cr<sub>2</sub>O<sub>3</sub>), and Silicon dioxide (SiO<sub>2</sub>), to evaluate combustion performance, and emission characteristics of a single-cylinder diesel engine under various load conditions. Incorporating Cr<sub>2</sub>O<sub>3</sub> nanoparticles into the CGSB20 biodiesel blend yielded significant improvements in BTE, coupled with BSFC reduction. Specifically, in the CGSB20 + Cr<sub>2</sub>O<sub>3</sub> fuel mixture, BTE increased notably by 31.2 %, reaching a value of 0.33 g/kWh for BSFC. Similarly, for the CGSB20 + SiO<sub>2</sub> and CGSB20 + TiO<sub>2</sub> blends, BTE experienced enhancements of 29.2 % and 28.1 %, respectively, while BSFC values were lowered to 0.37 and 0.4 g/kWh. Furthermore, the unchanging dispersal of nanoparticles within the CGSB20 blend exhibited extraordinary cylinder pressure and HRR values, reaching 77 bar and 34.2 J/CA, respectively. The CGSB20+ Cr<sub>2</sub>O<sub>3</sub> blend yielded favorable emissions outcomes. Specifically, CO, NOx, UHC, and smoke emissions were approximately 4.5 g/kWh, 725 ppm, 0.11 g/kWh, and 23.6 %, respectively.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142431972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.csite.2024.105228
This study aims to develop an environmentally friendly multi-energy system for sustainable production of electricity, cooling and hydrogen. The study introduces a pioneering geothermal-based system, integrating an ejector refrigeration cycle, a dual-loop organic Rankine cycle, and a hydrogen production unit with proton exchange membrane electrolyzers. The study provides a thorough analysis of the system's energy and exergy performance, as well as its economic feasibility. Through sensitivity and parametric analyses, the research identifies key parameters that significantly influence system performance. The system's innovative design promises minimal environmental impact while delivering multifaceted performance: generating 1.38 MW of electricity, supplying 436 kW of cooling load, and producing 5.39 kg/h of hydrogen. In the exergy analysis, Evaporator1 is identified as the primary contributor to exergy loss, representing 34 % of the total exergy destruction. This is followed by the electrolysis unit, the condenser, and the ejector refrigeration cycle, which contribute 18 %, 14 %, and 12 %, respectively. The system achieves optimal efficiency at an organic Rankine cycle turbine1 inlet temperature of 387 K, yielding a power generation of 885.4 kW and an exergy efficiency of 26.7 %. Beyond this temperature, any further increase leads to a decline in power output due to operational disturbances. A multi-criteria optimization using genetic algorithm is applied, resulting in an optimized system with a cost rate of 18.13 $/h and an exergy efficiency of 38.96 %.
{"title":"Development of a geothermal-driven multi-output scheme for electricity, cooling, and hydrogen production: Techno-economic assessment and genetic algorithm-based optimization","authors":"","doi":"10.1016/j.csite.2024.105228","DOIUrl":"10.1016/j.csite.2024.105228","url":null,"abstract":"<div><div>This study aims to develop an environmentally friendly multi-energy system for sustainable production of electricity, cooling and hydrogen. The study introduces a pioneering geothermal-based system, integrating an ejector refrigeration cycle, a dual-loop organic Rankine cycle, and a hydrogen production unit with proton exchange membrane electrolyzers. The study provides a thorough analysis of the system's energy and exergy performance, as well as its economic feasibility. Through sensitivity and parametric analyses, the research identifies key parameters that significantly influence system performance. The system's innovative design promises minimal environmental impact while delivering multifaceted performance: generating 1.38 MW of electricity, supplying 436 kW of cooling load, and producing 5.39 kg/h of hydrogen. In the exergy analysis, Evaporator1 is identified as the primary contributor to exergy loss, representing 34 % of the total exergy destruction. This is followed by the electrolysis unit, the condenser, and the ejector refrigeration cycle, which contribute 18 %, 14 %, and 12 %, respectively. The system achieves optimal efficiency at an organic Rankine cycle turbine1 inlet temperature of 387 K, yielding a power generation of 885.4 kW and an exergy efficiency of 26.7 %. Beyond this temperature, any further increase leads to a decline in power output due to operational disturbances. A multi-criteria optimization using genetic algorithm is applied, resulting in an optimized system with a cost rate of 18.13 $/h and an exergy efficiency of 38.96 %.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.csite.2024.105244
We investigated the adsorption of ifosfamide (IFS) on the outer surface of zigzag (10, 0) carbon nanotubes (CNT), boron nitride nanotubes (BNNT), and silicon carbon nanotubes (SiCNT), using density functional theory (DFT) calculations at the PBE-D3 level in a water solvent phase. Based on zero-point corrected binding energies (Ebin), IFS exhibits chemisorption through its O-head and Cl-head on CNT (−1.05 eV) compared to BNNT (−0.93 eV), characterized by covalent interaction. In contrast, IFS undergoes physisorption via its O-head on SiCNT with binding energy of −0.68 eV as the most stable model this interaction is driven by electrostatic forces. The formation of complexes between the drug and nanotubes is influenced by charge transfer dynamics. Our thermodynamic analysis demonstrates the Gibbs free energy (ΔG) and enthalpy energy (ΔH) for all models are exothermic and spontaneous. The observed decrease in binding energy for BNNT and CNT correlates with changes in their energy gap, dipole moment, and charge transfer upon IFS adsorption. Notably, SiCNT exhibits a different response with a significant energy gap change leading to an increase in dipole moment and charge transfer. These findings suggest that these nanotubes demonstrate promising sensitivity to the presence of IFS and could be explored as potential drug delivery systems for this drug.
{"title":"A first-principles adsorption study of functionalized carbon, boron nitride, silicon carbon nanotubes with ifosfamide as vehicles for drug delivery: Thermal analysis","authors":"","doi":"10.1016/j.csite.2024.105244","DOIUrl":"10.1016/j.csite.2024.105244","url":null,"abstract":"<div><div>We investigated the adsorption of ifosfamide (IFS) on the outer surface of zigzag (10, 0) carbon nanotubes (CNT), boron nitride nanotubes (BNNT), and silicon carbon nanotubes (SiCNT), using density functional theory (DFT) calculations at the PBE-D3 level in a water solvent phase. Based on zero-point corrected binding energies (E<sub>bin</sub>), IFS exhibits chemisorption through its O-head and Cl-head on CNT (−1.05 eV) compared to BNNT (−0.93 eV), characterized by covalent interaction. In contrast, IFS undergoes physisorption via its O-head on SiCNT with binding energy of −0.68 eV as the most stable model this interaction is driven by electrostatic forces. The formation of complexes between the drug and nanotubes is influenced by charge transfer dynamics. Our thermodynamic analysis demonstrates the Gibbs free energy (ΔG) and enthalpy energy (ΔH) for all models are exothermic and spontaneous. The observed decrease in binding energy for BNNT and CNT correlates with changes in their energy gap, dipole moment, and charge transfer upon IFS adsorption. Notably, SiCNT exhibits a different response with a significant energy gap change leading to an increase in dipole moment and charge transfer. These findings suggest that these nanotubes demonstrate promising sensitivity to the presence of IFS and could be explored as potential drug delivery systems for this drug.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-04DOI: 10.1016/j.csite.2024.105231
Artificial neural networks have revolutionized machine learning by providing exceptional capabilities for modeling complicated mechanisms and solving various challenges. Backpropagation is an important training technique in the field of artificial neural networks. However, this technique must be optimized when working with complicated fluid dynamics. This study analyzes the three-dimensional radiative flow of a tangent hyperbolic fluid driven by the Cattaneo-Christov flux system across a porous stretching sheet using ANN backpropagation enhanced by Bayesian Regularization approach. Heat and mass transfer analysis includes thermal radiation, chemical reactions and Cattaneo-Christov flux model. Porosity, radiation, chemical reaction rate, and ion slip effect are among the important physical characteristics that are modified to see how they affect fluid dynamics. Using MATLAB's BVP4C solver, the velocity, temperature, and concentration profiles that result from these model equations provide the training dataset for ANNs. The dataset is divided into 80 % for training, 10 % for testing, and 10 % for validation. Performance plots, regression graphs, and error histograms are used to analyze the performance of the LMT-based ANN and demonstrate its high accuracy and efficiency. With an R2 value of 1, the ANN produced a mean squared error of around 10⁻11. Fluid mobility drops as the magnetic parameter grows, while the thermal profile exhibits an increasing trend. Similarly, decreasing fluid velocity is the outcome of raising the porosity parameter. The study's conclusions have great potential for use in sectors that need sophisticated cooling and heating equipment.
{"title":"Efficiency analysis of solar radiation on chemical radioactive nanofluid flow over a porous surface with magnetic field","authors":"","doi":"10.1016/j.csite.2024.105231","DOIUrl":"10.1016/j.csite.2024.105231","url":null,"abstract":"<div><div>Artificial neural networks have revolutionized machine learning by providing exceptional capabilities for modeling complicated mechanisms and solving various challenges. Backpropagation is an important training technique in the field of artificial neural networks. However, this technique must be optimized when working with complicated fluid dynamics. This study analyzes the three-dimensional radiative flow of a tangent hyperbolic fluid driven by the Cattaneo-Christov flux system across a porous stretching sheet using ANN backpropagation enhanced by Bayesian Regularization approach. Heat and mass transfer analysis includes thermal radiation, chemical reactions and Cattaneo-Christov flux model. Porosity, radiation, chemical reaction rate, and ion slip effect are among the important physical characteristics that are modified to see how they affect fluid dynamics. Using MATLAB's BVP4C solver, the velocity, temperature, and concentration profiles that result from these model equations provide the training dataset for ANNs. The dataset is divided into 80 % for training, 10 % for testing, and 10 % for validation. Performance plots, regression graphs, and error histograms are used to analyze the performance of the LMT-based ANN and demonstrate its high accuracy and efficiency. With an R<sup>2</sup> value of 1, the ANN produced a mean squared error of around 10⁻<sup>11</sup>. Fluid mobility drops as the magnetic parameter grows, while the thermal profile exhibits an increasing trend. Similarly, decreasing fluid velocity is the outcome of raising the porosity parameter. The study's conclusions have great potential for use in sectors that need sophisticated cooling and heating equipment.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-04DOI: 10.1016/j.csite.2024.105212
The coal-fired power plant (CFPP) coupled with the molten salt thermal energy storage system is a potential way to improve its flexibility and peak-shaving ability. The steam generation system (SGS) is a suitable choice to convert the feed water into hot steam by using the heat from the molten salt. In this paper, the schematic of an SGS coupled with the CFPP is presented. A dynamic model of the SGS basing lump parameter method is established and validated to investigate its dynamic response characteristics. Five different disturbance experiments including feed water inlet parameters, molten salt inlet parameters and medium pressure steam valve, are conducted and analyzed. The dynamic response curves of molten salt and steam are obtained. Moreover, the load adjustment process of SGS with three different load changing rates (3 %, 6 %, 10 % Pe/min) under the rated conditions is compared and its influence on the SGS is analyzed. The temperature changing rates in the thick-wall components of SGS are within 2 °C/min which meets the safe operating standard. Based on the above results, the three elements control strategy with excellent robustness for the SGS safety operation is proposed and demonstrated. The results show that the response time for the SGS load regulation process and the water level fluctuation have been significantly improved as the three elements control strategy is imposed. The water level can be stabilized in 200 s with tiny fluctuation when the SGS loads down 10 % thermal load with 10 % Pe/min load changing rate. These results could provide useful references for the design and control strategy making of the CFPP coupled with the molten salt thermal energy storage system.
{"title":"Dynamic simulation and control strategy development of molten salt steam generation system for coal-fired power plant flexible retrofit","authors":"","doi":"10.1016/j.csite.2024.105212","DOIUrl":"10.1016/j.csite.2024.105212","url":null,"abstract":"<div><div>The coal-fired power plant (CFPP) coupled with the molten salt thermal energy storage system is a potential way to improve its flexibility and peak-shaving ability. The steam generation system (SGS) is a suitable choice to convert the feed water into hot steam by using the heat from the molten salt. In this paper, the schematic of an SGS coupled with the CFPP is presented. A dynamic model of the SGS basing lump parameter method is established and validated to investigate its dynamic response characteristics. Five different disturbance experiments including feed water inlet parameters, molten salt inlet parameters and medium pressure steam valve, are conducted and analyzed. The dynamic response curves of molten salt and steam are obtained. Moreover, the load adjustment process of SGS with three different load changing rates (3 %, 6 %, 10 % Pe/min) under the rated conditions is compared and its influence on the SGS is analyzed. The temperature changing rates in the thick-wall components of SGS are within 2 °C/min which meets the safe operating standard. Based on the above results, the three elements control strategy with excellent robustness for the SGS safety operation is proposed and demonstrated. The results show that the response time for the SGS load regulation process and the water level fluctuation have been significantly improved as the three elements control strategy is imposed. The water level can be stabilized in 200 s with tiny fluctuation when the SGS loads down 10 % thermal load with 10 % Pe/min load changing rate. These results could provide useful references for the design and control strategy making of the CFPP coupled with the molten salt thermal energy storage system.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-04DOI: 10.1016/j.csite.2024.105234
The constant temperature rise on the solar panel surface causes a deterioration of electrical power generation. This article is provided with the performance of photovoltaic thermal (PVT) collector through cerium oxide with water as a base fluid. A small percentage of incoming radiation is transformed into electricity and rest of them is wasted as hot energy, the panel surface temperature will confine the performance of PV module. The research's objectives were to develop and construct a photovoltaic/thermal collector and evaluate its thermal and electrical energy as an output. The experimental investigation of PVT collector with two different concentration of cerium oxide 0.5 and 1.0 LPM (litres per minute). As per the investigations on the PVT collector results were obtained as electrical performance of collector was attained about 18.56 %, 19.12 % for the flow rate of 0.5 and 1.0 LPM. Similarly, thermal performance was achieved 48.38 %, 54.03 % for the flow rate of 0.5 and 1.0 LPM. Thermal conductivity of cerium oxide nano fluid was much better than the air and water. It was observed that employing a nano fluid to the receiver might increase the efficiency around 5–10 %, compared to utilising water as a base fluid, water can only generate 3–7 %. As a cooling medium, air has a relatively low production capacity between 2 and 3 %.
{"title":"Performance investigation on PVT collector with cerium oxide nano fluids","authors":"","doi":"10.1016/j.csite.2024.105234","DOIUrl":"10.1016/j.csite.2024.105234","url":null,"abstract":"<div><div>The constant temperature rise on the solar panel surface causes a deterioration of electrical power generation. This article is provided with the performance of photovoltaic thermal (PVT) collector through cerium oxide with water as a base fluid. A small percentage of incoming radiation is transformed into electricity and rest of them is wasted as hot energy, the panel surface temperature will confine the performance of PV module. The research's objectives were to develop and construct a photovoltaic/thermal collector and evaluate its thermal and electrical energy as an output. The experimental investigation of PVT collector with two different concentration of cerium oxide 0.5 and 1.0 LPM (litres per minute). As per the investigations on the PVT collector results were obtained as electrical performance of collector was attained about 18.56 %, 19.12 % for the flow rate of 0.5 and 1.0 LPM. Similarly, thermal performance was achieved 48.38 %, 54.03 % for the flow rate of 0.5 and 1.0 LPM. Thermal conductivity of cerium oxide nano fluid was much better than the air and water. It was observed that employing a nano fluid to the receiver might increase the efficiency around 5–10 %, compared to utilising water as a base fluid, water can only generate 3–7 %. As a cooling medium, air has a relatively low production capacity between 2 and 3 %.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-03DOI: 10.1016/j.csite.2024.105230
The effort to reduce CO2 and NOx emissions plays a crucial role in mitigating climate change, improving air quality, complying with environmental regulations, and promoting clean technology innovation. Ammonia, as an emission-free fuel, shows significant potential as a co-firing agent with Coal in coal-fired steam power plants (CFSPP). Previous studies have demonstrated promising results in emission reduction through ammonia co-firing. This research presents a numerical analysis based on Computational Fluid Dynamics (CFD) to investigate the co-firing of ammonia with low-calorific Coal (LRC) in the CFSPP Pangkalan Susu Units 3 and 4, with a capacity of 210 MW. The study employs fluid flow modelling and chemical reaction analysis using the Discrete Phase Model (DPM) to provide accurate predictions of temperature distribution and pollutant concentrations in pulverized coal boilers. Cofiring simulations were conducted with ammonia additions of 5 % and 15 % on a calorific basis. Injection experiments from each burner (A-D) were performed to identify the optimal injection location. The simulation results indicate changes in combustion characteristics, particularly in temperature distribution. The main finding reveals a temperature decrease when ammonia is added as a co-firing material, attributed to the higher H2O content, which leads to increased moisture losses. In terms of efficiency, co-firing showed a decline compared to the baseline combustion of 100 % LRC coal due to the more significant moisture losses. The highest reduction in CO2 emissions was observed when 15 % ammonia was injected from burner B in case #6, with a mass fraction value of 0.171 at the boiler outlet. Similarly, the most significant reduction in NOx emissions occurred with a 15 % ammonia co-firing from burner B, yielding a mass fraction value of 8.81E-04 at the boiler outlet. This co-firing technology is expected to enhance decarbonization efforts and optimize the use of renewable energy in the future.
{"title":"Numerical simulation of co-firing LRC and ammonia in Pangkalan Susu 3 & 4 coal-fired steam power plant (CFSPP) capacity 210 megawatts","authors":"","doi":"10.1016/j.csite.2024.105230","DOIUrl":"10.1016/j.csite.2024.105230","url":null,"abstract":"<div><div>The effort to reduce CO<sub>2</sub> and NO<sub>x</sub> emissions plays a crucial role in mitigating climate change, improving air quality, complying with environmental regulations, and promoting clean technology innovation. Ammonia, as an emission-free fuel, shows significant potential as a co-firing agent with Coal in coal-fired steam power plants (CFSPP). Previous studies have demonstrated promising results in emission reduction through ammonia co-firing. This research presents a numerical analysis based on Computational Fluid Dynamics (CFD) to investigate the co-firing of ammonia with low-calorific Coal (LRC) in the CFSPP Pangkalan Susu Units 3 and 4, with a capacity of 210 MW. The study employs fluid flow modelling and chemical reaction analysis using the Discrete Phase Model (DPM) to provide accurate predictions of temperature distribution and pollutant concentrations in pulverized coal boilers. Cofiring simulations were conducted with ammonia additions of 5 % and 15 % on a calorific basis. Injection experiments from each burner (A-D) were performed to identify the optimal injection location. The simulation results indicate changes in combustion characteristics, particularly in temperature distribution. The main finding reveals a temperature decrease when ammonia is added as a co-firing material, attributed to the higher H<sub>2</sub>O content, which leads to increased moisture losses. In terms of efficiency, co-firing showed a decline compared to the baseline combustion of 100 % LRC coal due to the more significant moisture losses. The highest reduction in CO<sub>2</sub> emissions was observed when 15 % ammonia was injected from burner B in case #6, with a mass fraction value of 0.171 at the boiler outlet. Similarly, the most significant reduction in NO<sub>x</sub> emissions occurred with a 15 % ammonia co-firing from burner B, yielding a mass fraction value of 8.81E-04 at the boiler outlet. This co-firing technology is expected to enhance decarbonization efforts and optimize the use of renewable energy in the future.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142442659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-03DOI: 10.1016/j.csite.2024.105242
Owing to higher thermal conductivity, nanofluids have the potential to be the coolant for various applications ranging from internal to external flows. A two-phase model is implemented to model the interaction between nanoparticles and base fluid to obtain accurate results. Heat transfer and entropy generation characteristics of nanofluid (Al2O3 and water) flow over bluff bodies such as circular and square cylinders for steady (20 < Re < 100) and unsteady (Re = 150 and 300) flow conditions have been carried out for various volume fractions (0.5–2 %). The same has been expressed in quantitative and qualitative aspects with parameters such as mean Nusselt number, surface Nusselt number, heat transfer enhancement ratio, and entropy generation. Heat transfer rate increases with an increase in flow rate and volume fraction for both steady and unsteady flow. Heat transfer enhancement in steady flow ranges from 1.10 to 1.35. For unsteady flow (Re = 150 & Re = 300), nanofluid's heat transfer enhancement ratio is higher than water in the range of 1.10–1.8. This is attributed to the early separation of flow and the presence of large recirculatory regions. With the increase in Re, the entropy generation decreases for circular and square cylinders. Compared to nanofluid, the entropy generation is higher for water.
由于具有较高的热导率，纳米流体有可能成为从内部流到外部流等各种应用的冷却剂。为了获得准确的结果，采用了一个两相模型来模拟纳米粒子与基液之间的相互作用。在各种体积分数（0.5%-2%）的稳定（20 < Re < 100）和非稳定（Re = 150 和 300）流动条件下，纳米流体（Al2O3 和水）在圆形和方形圆柱体等崖体上流动时的传热和熵生成特性已经得到验证。在定量和定性方面，同样使用了平均努塞尔特数、表面努塞尔特数、传热增强比和熵生成等参数。在稳定流和非稳定流中，传热率随着流速和体积分数的增加而增加。稳定流的传热增强率在 1.10 到 1.35 之间。对于非稳定流（Re = 150 & Re = 300），纳米流体的传热增强比高于水，范围在 1.10-1.8 之间。这归因于流体的早期分离和大量再循环区域的存在。随着 Re 值的增加，圆形和方形圆柱体的熵产生量减少。与纳米流体相比，水的熵产生量更高。
{"title":"Heat transfer and entropy generation characteristics of nanofluid flow over bluff bodies under steady and unsteady flow: A two-phase approach","authors":"","doi":"10.1016/j.csite.2024.105242","DOIUrl":"10.1016/j.csite.2024.105242","url":null,"abstract":"<div><div>Owing to higher thermal conductivity, nanofluids have the potential to be the coolant for various applications ranging from internal to external flows. A two-phase model is implemented to model the interaction between nanoparticles and base fluid to obtain accurate results. Heat transfer and entropy generation characteristics of nanofluid (Al<sub>2</sub>O<sub>3</sub> and water) flow over bluff bodies such as circular and square cylinders for steady (20 < Re < 100) and unsteady (Re = 150 and 300) flow conditions have been carried out for various volume fractions (0.5–2 %). The same has been expressed in quantitative and qualitative aspects with parameters such as mean Nusselt number, surface Nusselt number, heat transfer enhancement ratio, and entropy generation. Heat transfer rate increases with an increase in flow rate and volume fraction for both steady and unsteady flow. Heat transfer enhancement in steady flow ranges from 1.10 to 1.35. For unsteady flow (Re = 150 & Re = 300), nanofluid's heat transfer enhancement ratio is higher than water in the range of 1.10–1.8. This is attributed to the early separation of flow and the presence of large recirculatory regions. With the increase in Re, the entropy generation decreases for circular and square cylinders. Compared to nanofluid, the entropy generation is higher for water.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-03DOI: 10.1016/j.csite.2024.105240
The island mining face in coal mines often encounters stress concentration and significant air leakage, elevating the risk of rock burst and spontaneous combustion of residual coal in the goaf. This study centers on the investigation of the 9305 island mining face within a mine situated in Shandong Province, China. Leveraging the features of coal spontaneous combustion and data from microseismic and gas monitoring throughout the mining process, a novel method for calculating safe mining speeds under compound disasters is introduced. The safe mining speed of the 9305 island mining face is stratified, and a prevention and control technology integrating long distance directional drilling for impact-spontaneous combustion compound disasters is proposed. Findings suggest that to mitigate spontaneous combustion of residual coal, considering the seam's spontaneous combustion tendency, the safe mining speed should exceed 3.7 m per day. Accounting for the distribution of microseismic events during coal seam extraction, the safe mining speed is maintained below 4.8 m per day in the unprotected mining area and capped at 8 m per day in the protected zone. Through a comprehensive analysis considering coal seam spontaneous combustion tendency, impact tendency, and time to coal seam oxidation to critical temperature, the safe mining speed for the island mining face ranges from 3.7 m per day to 4.8 m per day in the unprotected area and from 5.14 m per day to 8 m per day in the protected area. The proposed long distance directional drilling 'one hole, multiple purposes' scheme enables an integrated approach encompassing pressure relief before coal seam extraction, water injection during mining, and grouting post-mining. This method effectively prevents and controls the compound disasters of rock burst and coal spontaneous combustion, presenting innovative technical solutions for the safe extraction of coal resources.
{"title":"Compound disaster characteristics of rock burst and coal spontaneous combustion in island mining face: A case study","authors":"","doi":"10.1016/j.csite.2024.105240","DOIUrl":"10.1016/j.csite.2024.105240","url":null,"abstract":"<div><div>The island mining face in coal mines often encounters stress concentration and significant air leakage, elevating the risk of rock burst and spontaneous combustion of residual coal in the goaf. This study centers on the investigation of the 9305 island mining face within a mine situated in Shandong Province, China. Leveraging the features of coal spontaneous combustion and data from microseismic and gas monitoring throughout the mining process, a novel method for calculating safe mining speeds under compound disasters is introduced. The safe mining speed of the 9305 island mining face is stratified, and a prevention and control technology integrating long distance directional drilling for impact-spontaneous combustion compound disasters is proposed. Findings suggest that to mitigate spontaneous combustion of residual coal, considering the seam's spontaneous combustion tendency, the safe mining speed should exceed 3.7 m per day. Accounting for the distribution of microseismic events during coal seam extraction, the safe mining speed is maintained below 4.8 m per day in the unprotected mining area and capped at 8 m per day in the protected zone. Through a comprehensive analysis considering coal seam spontaneous combustion tendency, impact tendency, and time to coal seam oxidation to critical temperature, the safe mining speed for the island mining face ranges from 3.7 m per day to 4.8 m per day in the unprotected area and from 5.14 m per day to 8 m per day in the protected area. The proposed long distance directional drilling 'one hole, multiple purposes' scheme enables an integrated approach encompassing pressure relief before coal seam extraction, water injection during mining, and grouting post-mining. This method effectively prevents and controls the compound disasters of rock burst and coal spontaneous combustion, presenting innovative technical solutions for the safe extraction of coal resources.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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