Pub Date : 2024-09-17eCollection Date: 2024-10-01DOI: 10.1515/cppm-2024-0038
Alam Nawaz Khan Wardag, Faïçal Larachi
Gas-solid fluidized bed reactors exhibit improved heat and mass transfer performance as compared to packed beds. Corrugated walls installed in narrow gas-solid bubbling fluidized bed (CWBFB) enclosures have been observed to decrease minimum bubbling velocity, reduce bubble size, improve gas distribution, provide stable operation, and minimize particle carryover or loss. Thorough analyses of the wall-to-bed heat transfer coefficient in flat- (FWBFB) and corrugated- (CWBFB) wall bubbling fluidized beds have been performed for a variety of operating conditions and geometric parameters. Fast-response self-adhesive heat flux probes and thermocouples were used to simultaneously measure the wall-to-bed heat flux, surface and bed temperatures, and were used to determine the heat transfer coefficient (HTC) at various axial and lateral locations. For a given set of parameters, a significant increase in HTC was observed at lower gas flow rates in CWBFB as compared to FWBFB. It was shown that CWBFB inventory required lower Umb (gas flow rate) as compared to FWBFB. Full 3-D transient Euler-Euler CFD simulations using the kinetic theory of granular flow were also performed, which confirmed the experimental results.
{"title":"Heat transfer efficiency in gas-solid fluidized beds with flat and corrugated walls.","authors":"Alam Nawaz Khan Wardag, Faïçal Larachi","doi":"10.1515/cppm-2024-0038","DOIUrl":"10.1515/cppm-2024-0038","url":null,"abstract":"<p><p>Gas-solid fluidized bed reactors exhibit improved heat and mass transfer performance as compared to packed beds. Corrugated walls installed in narrow gas-solid bubbling fluidized bed (CWBFB) enclosures have been observed to decrease minimum bubbling velocity, reduce bubble size, improve gas distribution, provide stable operation, and minimize particle carryover or loss. Thorough analyses of the wall-to-bed heat transfer coefficient in flat- (FWBFB) and corrugated- (CWBFB) wall bubbling fluidized beds have been performed for a variety of operating conditions and geometric parameters. Fast-response self-adhesive heat flux probes and thermocouples were used to simultaneously measure the wall-to-bed heat flux, surface and bed temperatures, and were used to determine the heat transfer coefficient (<i>HTC</i>) at various axial and lateral locations. For a given set of parameters, a significant increase in <i>HTC</i> was observed at lower gas flow rates in CWBFB as compared to FWBFB. It was shown that CWBFB inventory required lower <i>U</i> <sub>mb</sub> (gas flow rate) as compared to FWBFB. Full 3-D transient Euler-Euler CFD simulations using the kinetic theory of granular flow were also performed, which confirmed the experimental results.</p>","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":"19 5","pages":"795-807"},"PeriodicalIF":1.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11578628/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142686163","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}
Zhiqiang Long, Buqing Zhang, Guoqing Liu, Zhengxin Wu, Qiang Yan
Abstract In the current essay, the numerical investigation of heat transfer in an exchanger containing nanofluid with Cu nanoparticles in the presence of a new inserter is carried out. The equations governing the turbulent fluid flow have been solved utilizing single-phase models with the aid of the finite volume method in ANSYS-FLUENT software using the k-ε turbulence model for the Re number ranging from 4000 to 8000. Furthermore, the influence of Reynolds number, nanoparticle volume fraction, and geometric characteristics of turbulator on the friction factor and Nusselt number have been scrutinized. Outcomes reveal that the newly introduced inserter performs well and increases the Nusselt number by roughly 34–54 times and the friction coefficient by approximately 1.8–3.2 times compared to the smooth tube. It is also observed that a 2 % increase in the nanoparticles volume fraction has resulted in a rise in the Nusselt number by around 92 %. To attain the optimal performance of the presented turbulator, the longitudinal distance between the inserters is recommended as S/D = 5.27, for which Performance evaluation criteria values in the range of 3.01–9.23 in the Reynolds range under investigation are acquired.
{"title":"Enhancing heat transfer in tube heat exchanger containing water/Cu nanofluid by using turbulator","authors":"Zhiqiang Long, Buqing Zhang, Guoqing Liu, Zhengxin Wu, Qiang Yan","doi":"10.1515/cppm-2023-0079","DOIUrl":"https://doi.org/10.1515/cppm-2023-0079","url":null,"abstract":"Abstract In the current essay, the numerical investigation of heat transfer in an exchanger containing nanofluid with Cu nanoparticles in the presence of a new inserter is carried out. The equations governing the turbulent fluid flow have been solved utilizing single-phase models with the aid of the finite volume method in ANSYS-FLUENT software using the k-ε turbulence model for the Re number ranging from 4000 to 8000. Furthermore, the influence of Reynolds number, nanoparticle volume fraction, and geometric characteristics of turbulator on the friction factor and Nusselt number have been scrutinized. Outcomes reveal that the newly introduced inserter performs well and increases the Nusselt number by roughly 34–54 times and the friction coefficient by approximately 1.8–3.2 times compared to the smooth tube. It is also observed that a 2 % increase in the nanoparticles volume fraction has resulted in a rise in the Nusselt number by around 92 %. To attain the optimal performance of the presented turbulator, the longitudinal distance between the inserters is recommended as S/D = 5.27, for which Performance evaluation criteria values in the range of 3.01–9.23 in the Reynolds range under investigation are acquired.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":"15 s1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138971715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The present paper presents a numerical investigation of heat transfer in an exchanger fitted with a modified conical-shaped turbulator containing water/Fe2O3 nanofluid. The study aims to address the critical need for improved heat exchanger efficiency, a vital component in various industries, including the chemical, power generation, and food industries. The work focuses on achieving enhanced heat transfer performance within a smaller volume, a primary goal of modern technology and industrial processes. The innovation in this study lies in the design and analysis of a novel conical turbulator, which has not been explored extensively in the context of heat exchangers fitted with nanofluids. Unlike traditional methods, which often rely on active or semi-active means to enhance heat transfer, this research introduces a passive approach through the incorporation of turbulators. Specifically, the study investigates the use of perforated cone-shaped turbulators in conjunction with nanofluids to boost heat transfer performance. The research employs state-of-the-art computational fluid dynamics (CFD) models, allowing for a comprehensive evaluation of the turbulator’s performance across a wide range of Reynolds numbers (Re = 4000–20,000). It further examines the influence of various turbulator parameters, nanoparticle content, and geometry on heat transfer efficiency. Key findings indicate that the modified turbulator exhibits exceptional performance, increasing Nusselt numbers by 3.4–5.4 times and friction coefficients by 2.3–1.8 times compared to smooth pipes. Particularly noteworthy is the 92 % increase in the Nusselt number achieved with a mere 2 % increase in the Fe2O3 nanoparticle content. The present study introduces a novel passive heat transfer enhancement method using perforated cone-shaped turbulators and nanofluids, filling a significant gap in existing research. The innovative turbulator design and its substantial performance improvements offer promising prospects for achieving higher heat exchanger efficiency, making it a valuable contribution to thermal systems and heat transfer engineering.
{"title":"Enhancing heat exchanger efficiency with novel perforated cone-shaped turbulators and nanofluids: a computational study","authors":"Limin Wang, Junqiang Wang, Jiajia Tang, Xuliong Zho","doi":"10.1515/cppm-2023-0034","DOIUrl":"https://doi.org/10.1515/cppm-2023-0034","url":null,"abstract":"Abstract The present paper presents a numerical investigation of heat transfer in an exchanger fitted with a modified conical-shaped turbulator containing water/Fe2O3 nanofluid. The study aims to address the critical need for improved heat exchanger efficiency, a vital component in various industries, including the chemical, power generation, and food industries. The work focuses on achieving enhanced heat transfer performance within a smaller volume, a primary goal of modern technology and industrial processes. The innovation in this study lies in the design and analysis of a novel conical turbulator, which has not been explored extensively in the context of heat exchangers fitted with nanofluids. Unlike traditional methods, which often rely on active or semi-active means to enhance heat transfer, this research introduces a passive approach through the incorporation of turbulators. Specifically, the study investigates the use of perforated cone-shaped turbulators in conjunction with nanofluids to boost heat transfer performance. The research employs state-of-the-art computational fluid dynamics (CFD) models, allowing for a comprehensive evaluation of the turbulator’s performance across a wide range of Reynolds numbers (Re = 4000–20,000). It further examines the influence of various turbulator parameters, nanoparticle content, and geometry on heat transfer efficiency. Key findings indicate that the modified turbulator exhibits exceptional performance, increasing Nusselt numbers by 3.4–5.4 times and friction coefficients by 2.3–1.8 times compared to smooth pipes. Particularly noteworthy is the 92 % increase in the Nusselt number achieved with a mere 2 % increase in the Fe2O3 nanoparticle content. The present study introduces a novel passive heat transfer enhancement method using perforated cone-shaped turbulators and nanofluids, filling a significant gap in existing research. The innovative turbulator design and its substantial performance improvements offer promising prospects for achieving higher heat exchanger efficiency, making it a valuable contribution to thermal systems and heat transfer engineering.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":"14 4","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138603750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract A mathematical model was constructed to estimate the performance of an MFI-membrane reactor used for Fischer–Tropsch synthesis to produce a mixture of liquid hydrocarbons. In order to accurately evaluate the reactor’s performance a parametric study was performed. Under certain operational conditions, such as the total initial pressure in the reaction zone (1–4 MPa) and the hydrogen/carbon monoxide ratio (H2/CO: 1 to 2) on the performance of the studied reactor. The selectivity (productivity) of the hydrocarbon products (S i ), the quantity of hydrocarbons permiated (θ i ) and the separation factors of each space (α i ) were predicted. With increasing pressure, it is observed that θ CO and θ H 2 ${theta }_{{H}_{2}}$ are decreasing from 0.62 to 0.45 and from 0.55 to 0.49 respectively. However, as the H2/CO ratio rises, this measurement shows a slight increase. Aside from, the separation factors of the majority of the current species are unaffected by the H2/CO ratio increasing, while the separation factors of carbon monoxide and hydrogen are increasing. Similarly the selectivity of water, methane, carbon dioxide and ethane increases with increasing H2/CO ratio. Based on these findings it is revealed that the membrane can enable permeability for all species present in the products mixture with varying separation factors, and that the ability to separate species other than water from the reaction side is essentially non-existent.
摘要 建立了一个数学模型，以估算用于费托合成生产液态烃混合物的 MFI 膜反应器的性能。为了准确评估反应器的性能，进行了参数研究。在特定的操作条件下，如反应区的总初始压力（1-4 兆帕）和氢气/一氧化碳比率（H2/CO：1 至 2），会对所研究的反应器的性能产生影响。预测了碳氢化合物产物的选择性（生产率）（S i ）、碳氢化合物的过氧化量（θ i ）和各空间的分离系数（α i ）。随着压力的增加，θ CO 和 θ H 2 ${theta }_{H}_{2}}$ 分别从 0.62 降至 0.45 和从 0.55 降至 0.49。不过，随着 H2/CO 比值的上升，这一测量值略有增加。除此以外，当前大多数物种的分离因数不受 H2/CO 比率增加的影响，而一氧化碳和氢气的分离因数却在增加。同样，水、甲烷、二氧化碳和乙烷的选择性也随着 H2/CO 比率的增加而增加。根据这些发现，膜可以使产品混合物中存在的所有物质都具有不同的渗透性，分离因子也各不相同，而从反应侧分离水以外物质的能力基本上不存在。
{"title":"Mathematical modeling and evaluation of permeation and membrane separation performance for Fischer–Tropsch products in a hydrophilic membrane reactor","authors":"Dounia Alihellal, Sabrina Hadjam, Lemnouer Chibane","doi":"10.1515/cppm-2023-0016","DOIUrl":"https://doi.org/10.1515/cppm-2023-0016","url":null,"abstract":"Abstract A mathematical model was constructed to estimate the performance of an MFI-membrane reactor used for Fischer–Tropsch synthesis to produce a mixture of liquid hydrocarbons. In order to accurately evaluate the reactor’s performance a parametric study was performed. Under certain operational conditions, such as the total initial pressure in the reaction zone (1–4 MPa) and the hydrogen/carbon monoxide ratio (H2/CO: 1 to 2) on the performance of the studied reactor. The selectivity (productivity) of the hydrocarbon products (S i ), the quantity of hydrocarbons permiated (θ i ) and the separation factors of each space (α i ) were predicted. With increasing pressure, it is observed that θ CO and θ H 2 ${theta }_{{H}_{2}}$ are decreasing from 0.62 to 0.45 and from 0.55 to 0.49 respectively. However, as the H2/CO ratio rises, this measurement shows a slight increase. Aside from, the separation factors of the majority of the current species are unaffected by the H2/CO ratio increasing, while the separation factors of carbon monoxide and hydrogen are increasing. Similarly the selectivity of water, methane, carbon dioxide and ethane increases with increasing H2/CO ratio. Based on these findings it is revealed that the membrane can enable permeability for all species present in the products mixture with varying separation factors, and that the ability to separate species other than water from the reaction side is essentially non-existent.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":"30 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139211953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Gas sweetening with an aqueous solution of diethanolamine is a crucial and common process in natural gas processing. However, the process, particularly in the solvent regeneration section, consumes a substantial amount of energy, significantly escalating the cost of gas. This paper presents a simulation and optimization of an existing natural gas refinery plant using a lean vapor compression method. The simulation results indicate that the current process requires 2.73 GJ/tacid gas for solvent regeneration, with exergy destruction of 14,120.59 kW in the solvent regeneration section. The total annualized cost for the current process is 11.68 M$. A modified scheme is proposed to address the issue of high energy consumption and the associated costs. The proposed scheme demonstrates significant improvements in the aforementioned parameters. Specifically, energy for solvent regeneration, exergy destruction in the solvent regeneration section, total annualized cost, and cost of gas are reduced by 16.12 %, 25.04 %, 20.97 %, and 20 % compared to the current process, respectively. These improvements enhance the thermoeconomic indexes, making the proposed scheme a viable and cost-effective alternative to the current process.
{"title":"Energy, exergy, economic, and environmental analysis of natural gas sweetening process using lean vapor compression: a comparison study","authors":"Xiujun Sun, Lizhi Yuan","doi":"10.1515/cppm-2023-0040","DOIUrl":"https://doi.org/10.1515/cppm-2023-0040","url":null,"abstract":"Abstract Gas sweetening with an aqueous solution of diethanolamine is a crucial and common process in natural gas processing. However, the process, particularly in the solvent regeneration section, consumes a substantial amount of energy, significantly escalating the cost of gas. This paper presents a simulation and optimization of an existing natural gas refinery plant using a lean vapor compression method. The simulation results indicate that the current process requires 2.73 GJ/tacid gas for solvent regeneration, with exergy destruction of 14,120.59 kW in the solvent regeneration section. The total annualized cost for the current process is 11.68 M$. A modified scheme is proposed to address the issue of high energy consumption and the associated costs. The proposed scheme demonstrates significant improvements in the aforementioned parameters. Specifically, energy for solvent regeneration, exergy destruction in the solvent regeneration section, total annualized cost, and cost of gas are reduced by 16.12 %, 25.04 %, 20.97 %, and 20 % compared to the current process, respectively. These improvements enhance the thermoeconomic indexes, making the proposed scheme a viable and cost-effective alternative to the current process.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":"79 ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139243050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Spontaneous condensation occurs due to high steam speeds, leading to droplets in the stream that not only decrease performance but also hazard the security of the nozzle. This study aims to predict the position and size of suitable injected water droplets due to reduced losses due to liquid mass fraction. Firstly, the model of steam flow has been confirmed by experimental data using the Eulerian–Eulerian approach in Moore’s nozzle B. Then, the flow turbulence caused by phase change is modelled by k–w sst model. Then, the injection has applied in three sizes (coarse, medium, and fine) at four different positions of the nozzle and has analysed, which according to the findings of fine droplet size, has led to an enhancement in Mach number and on the other hand, injection in nucleation zone has resulted in a 7 % and 3 % reduction in wetness losses for the radius of coarse and fine droplets, respectively. It is predicted that the nucleation rate will decrease the smaller the injected droplets are in the nucleation region. Injection with a number droplet of 1.015 × 1018 and a radius of 0.013 (μm) in the nucleation zone of 10 mm after the throat increased by 4.5 % of Mach number.
{"title":"Numerical investigation of liquid mass fraction and condensation shock of wet-steam flow through convergence-divergence nozzle using strategic water droplets injection","authors":"Yijun Xu, Xuan Zhang, Yu Bai, Xin Li","doi":"10.1515/cppm-2023-0043","DOIUrl":"https://doi.org/10.1515/cppm-2023-0043","url":null,"abstract":"Abstract Spontaneous condensation occurs due to high steam speeds, leading to droplets in the stream that not only decrease performance but also hazard the security of the nozzle. This study aims to predict the position and size of suitable injected water droplets due to reduced losses due to liquid mass fraction. Firstly, the model of steam flow has been confirmed by experimental data using the Eulerian–Eulerian approach in Moore’s nozzle B. Then, the flow turbulence caused by phase change is modelled by k–w sst model. Then, the injection has applied in three sizes (coarse, medium, and fine) at four different positions of the nozzle and has analysed, which according to the findings of fine droplet size, has led to an enhancement in Mach number and on the other hand, injection in nucleation zone has resulted in a 7 % and 3 % reduction in wetness losses for the radius of coarse and fine droplets, respectively. It is predicted that the nucleation rate will decrease the smaller the injected droplets are in the nucleation region. Injection with a number droplet of 1.015 × 1018 and a radius of 0.013 (μm) in the nucleation zone of 10 mm after the throat increased by 4.5 % of Mach number.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":"54 12","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139254537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Unstable processes are challenging to control because they have one or more positive poles that produce unrestrained dynamic activity. Controlling such unstable plants becomes more challenging with the occurrence of the delay. This article presents a novel direct synthesis based sliding mode controller design for unstable second order plus dead-time processes. A sliding surface with three parameters has been considered. The continuous control law, which is responsible for maintaining the system mode to the desired sliding surface mode, has been obtained using the direct synthesis approach. The discontinuous control law parameters have been obtained using the differential evolution optimization technique. A desired reference model is considered for the direct synthesis method, and an objective function is constituted in terms of performance measure (integral absolute error) and control effort measure (total variation of controller output) for the optimization approach. Illustrative examples show the superiority of the proposed controller design method over recently reported literature, especially in terms of load rejection. The proposed controller approach is further extended to control the temperature of a nonlinear chemical reactor. Furthermore, the robustness of the proposed controller is also investigated for plant parametric uncertainty.
{"title":"Direct synthesis based sliding mode controller design for unstable second order with dead-time processes with its application on continuous stirred tank reactor","authors":"Mohammed Hasmat Ali, Md. Nishat Anwar","doi":"10.1515/cppm-2023-0062","DOIUrl":"https://doi.org/10.1515/cppm-2023-0062","url":null,"abstract":"Abstract Unstable processes are challenging to control because they have one or more positive poles that produce unrestrained dynamic activity. Controlling such unstable plants becomes more challenging with the occurrence of the delay. This article presents a novel direct synthesis based sliding mode controller design for unstable second order plus dead-time processes. A sliding surface with three parameters has been considered. The continuous control law, which is responsible for maintaining the system mode to the desired sliding surface mode, has been obtained using the direct synthesis approach. The discontinuous control law parameters have been obtained using the differential evolution optimization technique. A desired reference model is considered for the direct synthesis method, and an objective function is constituted in terms of performance measure (integral absolute error) and control effort measure (total variation of controller output) for the optimization approach. Illustrative examples show the superiority of the proposed controller design method over recently reported literature, especially in terms of load rejection. The proposed controller approach is further extended to control the temperature of a nonlinear chemical reactor. Furthermore, the robustness of the proposed controller is also investigated for plant parametric uncertainty.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":"24 3","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139271602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Microfluidic technology has garnered growing interest in diverse domains. The efficacy and precision of microfluidic devices are significantly influenced by micromixing processes. Micromixers, comprising microchannels designed to blend fluids within a confined space and limited flow pathway, constitute indispensable components of microfluidic systems. Among these components, the micromixer stands out as a critical element, tasked with achieving maximal mixing efficiency while imposing minimal pressure drop. This paper focusses on the numerical and experimental study the baffle-based split and recombine chamber (B-SARC) micromixers. The models of a curved wavy micromixer (without baffle) and the baffle-based split and recombine chamber (B-SARC) micromixers with three baffles such as square, triangular and teardrop shaped baffles been developed using COMSOL Multiphysics software. The mixing performance analysis has been carried out by studying the mixing index and pressure drop. The influence of baffle shapes i.e. square, triangular and teardrop shaped baffles of aspect ratio 1, 1.5 and 2 on mixing performance analysis has been investigated numerically, for widespread assortment of Reynolds numbers (Re) lies between 0.1 and 90. The polydimethylsiloxane (PDMS) baffle-based split and recombine chamber (B-SARC) micromixers have been fabricated. Further, the experimental analysis has been carried out. The experimental analysis for pressure drop as well as mixing index has been performed. A good agreement has been observed between experimental and computational results which leads to validation of the computational results. The results revel the role of diffusion at lower Reynolds numbers and the production of derivative flows owing to advection at higher Reynolds numbers within the considered range of Re.
{"title":"Numerical and experimental study of the baffle-based split and recombine chamber (B-SARC) micromixers","authors":"Sanjay A. Pawar, Vimal Kumar Chouksey","doi":"10.1515/cppm-2023-0053","DOIUrl":"https://doi.org/10.1515/cppm-2023-0053","url":null,"abstract":"Abstract Microfluidic technology has garnered growing interest in diverse domains. The efficacy and precision of microfluidic devices are significantly influenced by micromixing processes. Micromixers, comprising microchannels designed to blend fluids within a confined space and limited flow pathway, constitute indispensable components of microfluidic systems. Among these components, the micromixer stands out as a critical element, tasked with achieving maximal mixing efficiency while imposing minimal pressure drop. This paper focusses on the numerical and experimental study the baffle-based split and recombine chamber (B-SARC) micromixers. The models of a curved wavy micromixer (without baffle) and the baffle-based split and recombine chamber (B-SARC) micromixers with three baffles such as square, triangular and teardrop shaped baffles been developed using COMSOL Multiphysics software. The mixing performance analysis has been carried out by studying the mixing index and pressure drop. The influence of baffle shapes i.e. square, triangular and teardrop shaped baffles of aspect ratio 1, 1.5 and 2 on mixing performance analysis has been investigated numerically, for widespread assortment of Reynolds numbers (Re) lies between 0.1 and 90. The polydimethylsiloxane (PDMS) baffle-based split and recombine chamber (B-SARC) micromixers have been fabricated. Further, the experimental analysis has been carried out. The experimental analysis for pressure drop as well as mixing index has been performed. A good agreement has been observed between experimental and computational results which leads to validation of the computational results. The results revel the role of diffusion at lower Reynolds numbers and the production of derivative flows owing to advection at higher Reynolds numbers within the considered range of Re.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":"156 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135776661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Extensive research has been done to provide energy from renewable sources due to climate change, global warming and limited fossil resources. Due to its low energy density, biomass is one of the renewable energy sources that is not used directly. Biomass is a clean, renewable energy source with a zero carbon dioxide release rate. Gasification is a chemical process that converts carbonaceous materials like biomass into gaseous fuels or useful chemical raw materials for gasification to occur in an oxygen-deficient environment with a requirement for heat which needs mediators for the reaction, like air, oxygen, superheated steam, or a combination of these. This study has been conducted to investigate the impact of the type of biomass feed on the production of syngas using the steam gasification method. Therefore, rice husk, wood chip, wood residue, coffee bean and green waste are considered, and the impact of gasification temperature and steam to biomass ratio (S/B) is investigated. According to the results, wood residue produces the most hydrogen compared to other feeds. With the increase of gasification temperature, an increase-decrease trend in the mass flow rate of hydrogen and an increase trend in the mass flow rate of carbon monoxide can be seen. The hydrogen produced in wood residue is 855 kg/h at S/B of 0.2 as well as a gasification temperature of 1200 °C. The lowest mass flow rate of hydrogen and carbon monoxide is related to green waste feed.
{"title":"Numerical investigation of different biomass feedstock on syngas production using steam gasification and thermodynamic analysis","authors":"Hao Wu, Liping Zhang, Bing Xiao","doi":"10.1515/cppm-2023-0056","DOIUrl":"https://doi.org/10.1515/cppm-2023-0056","url":null,"abstract":"Abstract Extensive research has been done to provide energy from renewable sources due to climate change, global warming and limited fossil resources. Due to its low energy density, biomass is one of the renewable energy sources that is not used directly. Biomass is a clean, renewable energy source with a zero carbon dioxide release rate. Gasification is a chemical process that converts carbonaceous materials like biomass into gaseous fuels or useful chemical raw materials for gasification to occur in an oxygen-deficient environment with a requirement for heat which needs mediators for the reaction, like air, oxygen, superheated steam, or a combination of these. This study has been conducted to investigate the impact of the type of biomass feed on the production of syngas using the steam gasification method. Therefore, rice husk, wood chip, wood residue, coffee bean and green waste are considered, and the impact of gasification temperature and steam to biomass ratio (S/B) is investigated. According to the results, wood residue produces the most hydrogen compared to other feeds. With the increase of gasification temperature, an increase-decrease trend in the mass flow rate of hydrogen and an increase trend in the mass flow rate of carbon monoxide can be seen. The hydrogen produced in wood residue is 855 kg/h at S/B of 0.2 as well as a gasification temperature of 1200 °C. The lowest mass flow rate of hydrogen and carbon monoxide is related to green waste feed.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":"156 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135776660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Partial Least Squares (PLS) is a supervised multivariate statistical/machine learning technique, which is used for classification and identification/authentication of a variety of operating conditions in tomato juice concentrator/evaporator, yeast fermentation bioreactor and fluid catalytic cracking process plants. Data for the three processes were generated pertaining to different operating conditions (for each of them) including faulty ones by simulating their mechanistic models over 25 h. The simulated data at transient conditions were chosen for further processing. They were divided into training and testing data pools. After training, the developed PLS model could classify various process operating conditions 100 % accurately and identify unknown process operating conditions (simulated using training pool with certain degree of variations in them) pertaining to the processes.
{"title":"Classification and authentication of operating conditions in different processes using Partial Least Squares","authors":"Rubal Chandra, Madhusree Kundu","doi":"10.1515/cppm-2023-0074","DOIUrl":"https://doi.org/10.1515/cppm-2023-0074","url":null,"abstract":"Abstract Partial Least Squares (PLS) is a supervised multivariate statistical/machine learning technique, which is used for classification and identification/authentication of a variety of operating conditions in tomato juice concentrator/evaporator, yeast fermentation bioreactor and fluid catalytic cracking process plants. Data for the three processes were generated pertaining to different operating conditions (for each of them) including faulty ones by simulating their mechanistic models over 25 h. The simulated data at transient conditions were chosen for further processing. They were divided into training and testing data pools. After training, the developed PLS model could classify various process operating conditions 100 % accurately and identify unknown process operating conditions (simulated using training pool with certain degree of variations in them) pertaining to the processes.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":"47 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135217524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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