Sheharyar Malik, K. Anderson, N. Goel, T. Otanicar, S. Karimi
Flow control within a particle-based Concentrated Solar Power (CSP) system is essential in determining the heat transfer coefficient, and therefore, the power generation capability of these systems. There are three areas where particle flow control is significant: the receivers, storage tanks, and particle-sCO2 heat exchangers. The focus of this paper is on designing a new mechanism to control the flow in the particle-sCO2 heat exchangers due to the simplicity and potential cost savings when compared to the other areas of interest. The goal is for this new design to have quicker response times in terms of particle flowrate than a slide gate or flow control valve, which are designs currently used. The design resembles that of a chuck mechanism within a drill where a rotation of the sleeve elicits movement of the jaws both vertically and horizontally to close the outlet area of the nozzle. Additionally, this design will utilize the current actuator that is already used within these heat exchangers to reduce the complexity of implementation. The jaws are designed to be closed at an angle of 76° which is just slightly steeper than the hopper leading to the mechanism. Furthermore, this design can be tuned to limit particle bridging and other particle flow phenomena that result in blockages. The prototypes were 3D printed out of polylactic acid (PLA) and scaled up to 100%, 200%, and 400% to be able to observe the velocity profiles of the mechanism more clearly. Experiments are performed with this prototype to compare the inlet and outlet mass flow rates at different configurations of the jaws. The particles used in these experiments are 0.3mm HSP 40/70 that are commonly used in particle-based CSP systems.
{"title":"Designing a Particle Flow Control Apparatus","authors":"Sheharyar Malik, K. Anderson, N. Goel, T. Otanicar, S. Karimi","doi":"10.1115/imece2022-94820","DOIUrl":"https://doi.org/10.1115/imece2022-94820","url":null,"abstract":"\u0000 Flow control within a particle-based Concentrated Solar Power (CSP) system is essential in determining the heat transfer coefficient, and therefore, the power generation capability of these systems. There are three areas where particle flow control is significant: the receivers, storage tanks, and particle-sCO2 heat exchangers. The focus of this paper is on designing a new mechanism to control the flow in the particle-sCO2 heat exchangers due to the simplicity and potential cost savings when compared to the other areas of interest. The goal is for this new design to have quicker response times in terms of particle flowrate than a slide gate or flow control valve, which are designs currently used. The design resembles that of a chuck mechanism within a drill where a rotation of the sleeve elicits movement of the jaws both vertically and horizontally to close the outlet area of the nozzle. Additionally, this design will utilize the current actuator that is already used within these heat exchangers to reduce the complexity of implementation. The jaws are designed to be closed at an angle of 76° which is just slightly steeper than the hopper leading to the mechanism. Furthermore, this design can be tuned to limit particle bridging and other particle flow phenomena that result in blockages. The prototypes were 3D printed out of polylactic acid (PLA) and scaled up to 100%, 200%, and 400% to be able to observe the velocity profiles of the mechanism more clearly. Experiments are performed with this prototype to compare the inlet and outlet mass flow rates at different configurations of the jaws. The particles used in these experiments are 0.3mm HSP 40/70 that are commonly used in particle-based CSP systems.","PeriodicalId":292222,"journal":{"name":"Volume 8: Fluids Engineering; Heat Transfer and Thermal Engineering","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114442146","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}
In this study, performance enhancement of a two stage electrohydrodynamic (EHD) gas pump in a rectangular channel has been evaluated by experimental measurement and numerical simulations. This study is implemented by a two stage EHD gas pump with uneven voltages for 8 emitting electrodes configuration to seek the relation between the number of stages and applied voltages. The EHD pump is evaluated for a combination of three different operating voltages (20 kV, 24 kV, and 28 kV) for further enhancement in its performance. To achieve the maximum enhancement, the emitting electrodes of the EHD gas pump are flush mounted on the channel walls so that the corona wind produced directly disturbs the boundary layer thickness and improves gas pumping. Velocities are measured at three cross-sections along the tube length and then integrated to obtain the volume flow rate. The numerical results enable vivid flow visualizations inside the channel, providing a great understanding of the development of the flow. The two stages EHD gas pump, which can be produced and sustained air flows with a maximum volume flow rate is considered more efficient when it is operated with uneven applied voltages. The results show that EHD technique has a great potential for many engineering applications.
{"title":"Performance Enhancement of Two Stages EHD Gas Pump in a Rectangular Channel With Uneven Voltages","authors":"A. K. M. Monayem H. Mazumder","doi":"10.1115/imece2022-96022","DOIUrl":"https://doi.org/10.1115/imece2022-96022","url":null,"abstract":"\u0000 In this study, performance enhancement of a two stage electrohydrodynamic (EHD) gas pump in a rectangular channel has been evaluated by experimental measurement and numerical simulations. This study is implemented by a two stage EHD gas pump with uneven voltages for 8 emitting electrodes configuration to seek the relation between the number of stages and applied voltages. The EHD pump is evaluated for a combination of three different operating voltages (20 kV, 24 kV, and 28 kV) for further enhancement in its performance. To achieve the maximum enhancement, the emitting electrodes of the EHD gas pump are flush mounted on the channel walls so that the corona wind produced directly disturbs the boundary layer thickness and improves gas pumping. Velocities are measured at three cross-sections along the tube length and then integrated to obtain the volume flow rate. The numerical results enable vivid flow visualizations inside the channel, providing a great understanding of the development of the flow. The two stages EHD gas pump, which can be produced and sustained air flows with a maximum volume flow rate is considered more efficient when it is operated with uneven applied voltages. The results show that EHD technique has a great potential for many engineering applications.","PeriodicalId":292222,"journal":{"name":"Volume 8: Fluids Engineering; Heat Transfer and Thermal Engineering","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114560403","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}
Nathan Doshi, Jacob Hancox, Polakrit Karkhai, Cameryn Smith, Adam Tawakkol, S. White, E. Bristow, A. Hill, Brad C. McCoy, Margaret Nowicki
Currently, the system of locks and dams within the United States operate where each system has a different component and needs different parts to complete the routine maintenance checks and procedures. Having unique components and parts for each lock and dam system drastically increases the costs required for the United States Army Corps of Engineers (USACE) to operate and maintain these locks and dams. One way to reduce these costs is to work towards and recommend standardized components for a lock and dam system. This process, especially for construction projects, is vital because it allows for simplification in the build and production stages of a project as well as life cycle maintenance. Understanding hydraulic design for the inflow and outflow of a lock system was an important consideration for this design project. Reducing hawser forces while maximizing the efficiency of the filling and emptying process is the overall goal for the design. To minimize hawser forces, mitigating the effects of hydrodynamic and hydrostatic forces is essential. This research also strives to gain additional understanding of the dynamic, turbulent nature of water in a lock and dam system. In the Emsworth Lock and Dam system, the top of rock for the riverbed is significantly higher than normal presenting unique challenges for modeling and simulation, as well as physical model construction. Critical to the design of a physical model is the determination of an adequate scaling factor that will not significantly affect the natural hydraulic processes within the system. As such, it is essential that appropriate theories are applied to remain consistent with proven methods of hydraulic scaling. Before selecting a scaling ratio, determining space limitations and a conceptual design of the model was necessary. This assisted in visualizing the model in the available spaces to ensure the design and manufacturing plan was realistic. The model contains three components: a main lock chamber, a higher elevation water reservoir, and a lower elevation water reservoir. The component that is most controlling to the design is the main lock chamber; this component cannot be altered in any way to meet the requirements of the floor space because any modifications would affect the results of the hawser force testing, and the model would not appropriately match reality. The physical model will be verified using the Froude equation — an equation that drives performance of models that are dependent on gravity. As such, when conducting any inflow or outflow of the water in the system, it is essential that the velocity is controlled such that the Froude value is consistent with that of the actual Emsworth Lock and Dam. The model must match a Froude number of 0.052 to effectively represent reality.
{"title":"Designing a Physical Model for the Emsworth Lock and Dam Filling and Emptying System","authors":"Nathan Doshi, Jacob Hancox, Polakrit Karkhai, Cameryn Smith, Adam Tawakkol, S. White, E. Bristow, A. Hill, Brad C. McCoy, Margaret Nowicki","doi":"10.1115/imece2022-95481","DOIUrl":"https://doi.org/10.1115/imece2022-95481","url":null,"abstract":"\u0000 Currently, the system of locks and dams within the United States operate where each system has a different component and needs different parts to complete the routine maintenance checks and procedures. Having unique components and parts for each lock and dam system drastically increases the costs required for the United States Army Corps of Engineers (USACE) to operate and maintain these locks and dams. One way to reduce these costs is to work towards and recommend standardized components for a lock and dam system. This process, especially for construction projects, is vital because it allows for simplification in the build and production stages of a project as well as life cycle maintenance.\u0000 Understanding hydraulic design for the inflow and outflow of a lock system was an important consideration for this design project. Reducing hawser forces while maximizing the efficiency of the filling and emptying process is the overall goal for the design. To minimize hawser forces, mitigating the effects of hydrodynamic and hydrostatic forces is essential. This research also strives to gain additional understanding of the dynamic, turbulent nature of water in a lock and dam system. In the Emsworth Lock and Dam system, the top of rock for the riverbed is significantly higher than normal presenting unique challenges for modeling and simulation, as well as physical model construction. Critical to the design of a physical model is the determination of an adequate scaling factor that will not significantly affect the natural hydraulic processes within the system. As such, it is essential that appropriate theories are applied to remain consistent with proven methods of hydraulic scaling.\u0000 Before selecting a scaling ratio, determining space limitations and a conceptual design of the model was necessary. This assisted in visualizing the model in the available spaces to ensure the design and manufacturing plan was realistic. The model contains three components: a main lock chamber, a higher elevation water reservoir, and a lower elevation water reservoir. The component that is most controlling to the design is the main lock chamber; this component cannot be altered in any way to meet the requirements of the floor space because any modifications would affect the results of the hawser force testing, and the model would not appropriately match reality. The physical model will be verified using the Froude equation — an equation that drives performance of models that are dependent on gravity. As such, when conducting any inflow or outflow of the water in the system, it is essential that the velocity is controlled such that the Froude value is consistent with that of the actual Emsworth Lock and Dam. The model must match a Froude number of 0.052 to effectively represent reality.","PeriodicalId":292222,"journal":{"name":"Volume 8: Fluids Engineering; Heat Transfer and Thermal Engineering","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116793558","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}
In low temperature superconducting (LTS) magnets built using (cryogenic) liquid cooled superconductors, such as those designed for particle accelerators and thermonuclear fusion reactors, the operating stability and quench (sudden transition from superconducting to normal state) is a complex phenomenon. In most cases, the quenched magnet is isolated from the rest of the cryogenic system and the cryogenic fluid (helium) is expelled from the cryostat via a pressure relief valve (PRV) to prevent over-pressurization. This loss of cryogenic coolant (release to atmosphere), as well as the associated stored refrigeration results in increased operational cost (to replenish the helium), and recovery time for the LTS magnet to be operational following a quench. A novel concept for energy and cryogenic inventory management during a LTS magnet quench using direct contact (fluid mixing) heat exchange in a cryogenic buffer volume has been proposed and demonstrated. Development of a semi-analytical, one-dimensional, transient model to predict the boil-off flow generated during a quench, and the subsequent energy absorption (and pressurization) in the cryogenic buffer volume is discussed. The developed model can be used as a simplified tool for process and mechanical design of such a system.
{"title":"Analysis and Management of Thermal Energy Release During Quench in a Superconducting Magnet","authors":"N. Hasan, V. Ganni, P. Knudsen","doi":"10.1115/imece2022-95762","DOIUrl":"https://doi.org/10.1115/imece2022-95762","url":null,"abstract":"\u0000 In low temperature superconducting (LTS) magnets built using (cryogenic) liquid cooled superconductors, such as those designed for particle accelerators and thermonuclear fusion reactors, the operating stability and quench (sudden transition from superconducting to normal state) is a complex phenomenon. In most cases, the quenched magnet is isolated from the rest of the cryogenic system and the cryogenic fluid (helium) is expelled from the cryostat via a pressure relief valve (PRV) to prevent over-pressurization. This loss of cryogenic coolant (release to atmosphere), as well as the associated stored refrigeration results in increased operational cost (to replenish the helium), and recovery time for the LTS magnet to be operational following a quench. A novel concept for energy and cryogenic inventory management during a LTS magnet quench using direct contact (fluid mixing) heat exchange in a cryogenic buffer volume has been proposed and demonstrated. Development of a semi-analytical, one-dimensional, transient model to predict the boil-off flow generated during a quench, and the subsequent energy absorption (and pressurization) in the cryogenic buffer volume is discussed. The developed model can be used as a simplified tool for process and mechanical design of such a system.","PeriodicalId":292222,"journal":{"name":"Volume 8: Fluids Engineering; Heat Transfer and Thermal Engineering","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126186176","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}
Shashank Terala, S. Mazumder, G. Matharu, Dhaval Vaishnav, Syed Ali
A liquid water-urea mixture is stored onboard diesel vehicles and used for exhaust aftertreatment. In cold weather conditions, the mixture may freeze and the freezing process may span over a day. In the first part of our study (Journal of Thermal Science and Engineering Applications — Transactions of the ASME, Vol. 13, p. 011008, 2021) it was shown that traditional computational methods are impractical for modeling such large-duration freezing processes because of restrictions in the time-step size posed by numerical stability and physical time-scale considerations. A model, in which natural convection driven thermal transport is treated as a diffusive process, was developed and demonstrated. Since the flow field was not computed in this model, the computations were found to be orders of magnitude more efficient than traditional methods. This preliminary model did not account for the expansion of ice. Here, a new model that accounts for the expansion of ice and the consequent rise of the initial air-water/ice interface (ice dome formation) is presented. An additional conservation equation for excess volume fraction is introduced to this end and is solved using the unstructured finite-volume procedure and sub-time-stepping. Since the flow field is not computed, the air-water/ice interface is tracked using a new algorithm similar to the traditional volume-of-fluid method, but one that constructs fluxes using a diffusive formulation rather than an advective one. Validation studies in full-scale three-dimensional tanks show good agreement with measured temperature-time data. It is found that the air-water/ice interface first evolves to a concave shape before finally becoming a convex ice dome after full solidification.
{"title":"A Reduced Three-Phase Model for Solidification of Liquid in Large Tanks","authors":"Shashank Terala, S. Mazumder, G. Matharu, Dhaval Vaishnav, Syed Ali","doi":"10.1115/imece2022-95217","DOIUrl":"https://doi.org/10.1115/imece2022-95217","url":null,"abstract":"\u0000 A liquid water-urea mixture is stored onboard diesel vehicles and used for exhaust aftertreatment. In cold weather conditions, the mixture may freeze and the freezing process may span over a day. In the first part of our study (Journal of Thermal Science and Engineering Applications — Transactions of the ASME, Vol. 13, p. 011008, 2021) it was shown that traditional computational methods are impractical for modeling such large-duration freezing processes because of restrictions in the time-step size posed by numerical stability and physical time-scale considerations. A model, in which natural convection driven thermal transport is treated as a diffusive process, was developed and demonstrated. Since the flow field was not computed in this model, the computations were found to be orders of magnitude more efficient than traditional methods. This preliminary model did not account for the expansion of ice. Here, a new model that accounts for the expansion of ice and the consequent rise of the initial air-water/ice interface (ice dome formation) is presented. An additional conservation equation for excess volume fraction is introduced to this end and is solved using the unstructured finite-volume procedure and sub-time-stepping. Since the flow field is not computed, the air-water/ice interface is tracked using a new algorithm similar to the traditional volume-of-fluid method, but one that constructs fluxes using a diffusive formulation rather than an advective one. Validation studies in full-scale three-dimensional tanks show good agreement with measured temperature-time data. It is found that the air-water/ice interface first evolves to a concave shape before finally becoming a convex ice dome after full solidification.","PeriodicalId":292222,"journal":{"name":"Volume 8: Fluids Engineering; Heat Transfer and Thermal Engineering","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130946361","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}
Particle separation is an important process step across many fields. One technique being applied for separating solids such as blood components or sand particles from carrier fluids is the use of arrays of aligned posts called deterministic lateral arrays to bump particles to one side in the flow stream to induce separation. This technique may be useful for separation of deformable particles including oil droplets. The ability to efficiently separate two-phase industrial (oil/water) mixtures is key for future use of valuable resources. The ability to reclaim petroleum production water may be critical for the Central High Plains (Colorado, Kansas, New Mexico, Oklahoma, and Texas). Current drawdown trends in the High Plains alone suggest loss of up to 40% of the aquifer area by 2100 that will cause the switch from irrigated to dryland farming. Proving this technology is key to reuse of petroleum production water for crop irrigation or to replace water from currently failing aquifers in rich agricultural lands of the Central High Plains. We conducted experiments applying mesofluidic separation for flowing two-phase (oil/water) mixtures. Experiments were conducted using oil with water as the carrier fluid; separation was achieved over a range of oil-water concentrations. We describe the results of these experiments in this paper.
{"title":"Separating Oil-Water Mixtures Using Bump Arrays","authors":"J. Bamberger, L. Pease, C. Burns, M. Minette","doi":"10.1115/imece2022-95920","DOIUrl":"https://doi.org/10.1115/imece2022-95920","url":null,"abstract":"\u0000 Particle separation is an important process step across many fields. One technique being applied for separating solids such as blood components or sand particles from carrier fluids is the use of arrays of aligned posts called deterministic lateral arrays to bump particles to one side in the flow stream to induce separation. This technique may be useful for separation of deformable particles including oil droplets.\u0000 The ability to efficiently separate two-phase industrial (oil/water) mixtures is key for future use of valuable resources. The ability to reclaim petroleum production water may be critical for the Central High Plains (Colorado, Kansas, New Mexico, Oklahoma, and Texas). Current drawdown trends in the High Plains alone suggest loss of up to 40% of the aquifer area by 2100 that will cause the switch from irrigated to dryland farming. Proving this technology is key to reuse of petroleum production water for crop irrigation or to replace water from currently failing aquifers in rich agricultural lands of the Central High Plains.\u0000 We conducted experiments applying mesofluidic separation for flowing two-phase (oil/water) mixtures. Experiments were conducted using oil with water as the carrier fluid; separation was achieved over a range of oil-water concentrations. We describe the results of these experiments in this paper.","PeriodicalId":292222,"journal":{"name":"Volume 8: Fluids Engineering; Heat Transfer and Thermal Engineering","volume":"2 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130277820","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}
Squeezing bubbles in a tapered microgap has proved to be effective for improving flow stability in flow boiling. A previous study from our research group has successfully demonstrated using tapered microgap for transforming pool boiling into a self-sustained flow boiling-like system for cooling CPU through thermosiphon. To overcome the imaging challenges with nucleating vapor bubbles, the present work investigates the squeezing behaviour of air-injected bubbles between a tapered microgap with taper angles of 5°, 10°, and 15°. The air bubbles are injected at a rate of 3 ml/min, 15ml/min, and 30 ml/min in a pool of water. The bubble squeezing is recorded at 2000fps using a Photron high-speed camera. The experimental analysis compares the displacement and velocity of the advancing and receding bubble interfaces. The analysis found that in certain test cases, multiple bubbles coalesced while exiting the tapered microgap. In all the test cases, the receding interface of the bubble slingshots after detaching pushes the bubble out of the tapered microgap. The result from the current study provides an insight into the bubble flow and squeezing behavior that can be used for optimizing taper microgap geometries to enhance critical heat flux and heat transfer coefficient of two-phase, and air-injected single-phase heat transfer systems.
{"title":"Experimental Investigation of Taper Angle and Airflow Rate on Air-Injected Bubble Squeezing in a Tapered Microgap","authors":"Maharshi Y. Shukla, S. Kandlikar","doi":"10.1115/imece2022-97020","DOIUrl":"https://doi.org/10.1115/imece2022-97020","url":null,"abstract":"\u0000 Squeezing bubbles in a tapered microgap has proved to be effective for improving flow stability in flow boiling. A previous study from our research group has successfully demonstrated using tapered microgap for transforming pool boiling into a self-sustained flow boiling-like system for cooling CPU through thermosiphon. To overcome the imaging challenges with nucleating vapor bubbles, the present work investigates the squeezing behaviour of air-injected bubbles between a tapered microgap with taper angles of 5°, 10°, and 15°. The air bubbles are injected at a rate of 3 ml/min, 15ml/min, and 30 ml/min in a pool of water. The bubble squeezing is recorded at 2000fps using a Photron high-speed camera. The experimental analysis compares the displacement and velocity of the advancing and receding bubble interfaces. The analysis found that in certain test cases, multiple bubbles coalesced while exiting the tapered microgap. In all the test cases, the receding interface of the bubble slingshots after detaching pushes the bubble out of the tapered microgap. The result from the current study provides an insight into the bubble flow and squeezing behavior that can be used for optimizing taper microgap geometries to enhance critical heat flux and heat transfer coefficient of two-phase, and air-injected single-phase heat transfer systems.","PeriodicalId":292222,"journal":{"name":"Volume 8: Fluids Engineering; Heat Transfer and Thermal Engineering","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126507414","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}
Zahra Kamali Khanghah, M. M. Tenorio, J. Brown, Guilherme Mainieri Eymael, M. Ghashami
Passive thermal radiative cooling (PTRC) has drawn massive attention in the past few years due to its advantages, including excellent cooling potential, no emission of greenhouse gases, silent operation, low maintenance, and off-grid operation. PTRC has been successfully demonstrated to reduce the electricity consumption required for cooling and ventilation of buildings. Several radiative emitters have been studied in the literature, such as pigmented paints, nanoparticle-based coatings, photonic crystals, metamaterials, and polymers. Among them, polymers have proven to be inherently strong infrared (IR) emitters, scalable, low-cost, flexible, easy to apply, and durable candidates. In addition to these features, biopolymers are eco-friendly and currently abundant in the market. Despite their significant advantages, there have been limited studies on the applications of biopolymers for radiative cooling. In this study, we report promising performances from a commercially available, affordable, and applicable biopolymer, cellulose, as a PTRC emitter. We fabricated several cellulose films with various structural characteristics and thicknesses. The emissivity and reflectivity of these emitter surfaces were measured for the desired wavelengths and direction. The obtained measurements reveal relatively high magnitudes of diffuse emissivity in the atmospheric window and high reflectivity in the solar spectrum range. Using the materials’ reflectivity and emissivity data, we theoretically calculated the net cooling power and the expected temperature drop. Each emitter demonstrated high cooling power and considerable temperature reduction based on the average recorded weather conditions in Lincoln, NE.
{"title":"Investigation of Passive Radiative Cooling Using Biopolymers","authors":"Zahra Kamali Khanghah, M. M. Tenorio, J. Brown, Guilherme Mainieri Eymael, M. Ghashami","doi":"10.1115/imece2022-97143","DOIUrl":"https://doi.org/10.1115/imece2022-97143","url":null,"abstract":"\u0000 Passive thermal radiative cooling (PTRC) has drawn massive attention in the past few years due to its advantages, including excellent cooling potential, no emission of greenhouse gases, silent operation, low maintenance, and off-grid operation. PTRC has been successfully demonstrated to reduce the electricity consumption required for cooling and ventilation of buildings. Several radiative emitters have been studied in the literature, such as pigmented paints, nanoparticle-based coatings, photonic crystals, metamaterials, and polymers. Among them, polymers have proven to be inherently strong infrared (IR) emitters, scalable, low-cost, flexible, easy to apply, and durable candidates. In addition to these features, biopolymers are eco-friendly and currently abundant in the market. Despite their significant advantages, there have been limited studies on the applications of biopolymers for radiative cooling. In this study, we report promising performances from a commercially available, affordable, and applicable biopolymer, cellulose, as a PTRC emitter. We fabricated several cellulose films with various structural characteristics and thicknesses. The emissivity and reflectivity of these emitter surfaces were measured for the desired wavelengths and direction. The obtained measurements reveal relatively high magnitudes of diffuse emissivity in the atmospheric window and high reflectivity in the solar spectrum range. Using the materials’ reflectivity and emissivity data, we theoretically calculated the net cooling power and the expected temperature drop. Each emitter demonstrated high cooling power and considerable temperature reduction based on the average recorded weather conditions in Lincoln, NE.","PeriodicalId":292222,"journal":{"name":"Volume 8: Fluids Engineering; Heat Transfer and Thermal Engineering","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123045882","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}
E. Heisler, Siddharth Saurav, Aadesh Deshmukh, S. Mazumder, P. Sadayappan, H. Sundar
The phonon Boltzmann transport equation is a good model for heat transfer in nanometer scale structures such as semiconductor devices. Computational complexity is one of the main challenges in numerically solving this set of potentially thousands of nonlinearly coupled equations. Writing efficient code will involve careful optimization and choosing an effective parallelization strategy, requiring expertise in high performance computing, mathematical methods, and thermal physics. To address this challenge, we present the domain specific language and code generation software Finch. This language allows a domain scientist to enter the equations in a simple format, provide only basic mathematical functions used in the model, and generate efficient parallel code. Even very complex systems of equations such as phonon Boltzmann transport can be entered in a very simple, intuitive way. A feature of the framework is flexibility in numerical methods, computing environments, parallel strategies, and other aspects of the generated code. We demonstrate Finch on this problem using a variety of parallel strategies and model configurations to demonstrate the flexibility and ease of use.
{"title":"A Domain Specific Language Applied to Phonon Boltzmann Transport for Heat Conduction","authors":"E. Heisler, Siddharth Saurav, Aadesh Deshmukh, S. Mazumder, P. Sadayappan, H. Sundar","doi":"10.1115/imece2022-95034","DOIUrl":"https://doi.org/10.1115/imece2022-95034","url":null,"abstract":"\u0000 The phonon Boltzmann transport equation is a good model for heat transfer in nanometer scale structures such as semiconductor devices. Computational complexity is one of the main challenges in numerically solving this set of potentially thousands of nonlinearly coupled equations. Writing efficient code will involve careful optimization and choosing an effective parallelization strategy, requiring expertise in high performance computing, mathematical methods, and thermal physics. To address this challenge, we present the domain specific language and code generation software Finch. This language allows a domain scientist to enter the equations in a simple format, provide only basic mathematical functions used in the model, and generate efficient parallel code. Even very complex systems of equations such as phonon Boltzmann transport can be entered in a very simple, intuitive way. A feature of the framework is flexibility in numerical methods, computing environments, parallel strategies, and other aspects of the generated code. We demonstrate Finch on this problem using a variety of parallel strategies and model configurations to demonstrate the flexibility and ease of use.","PeriodicalId":292222,"journal":{"name":"Volume 8: Fluids Engineering; Heat Transfer and Thermal Engineering","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126808361","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}
Circulating tumor cells (CTCs) are known to be a primary indicator of vital diagnostic and clinical information for early-stage cancer detection. Effective separation of CTCs from blood is crucial for genetic characterization of CTCs, drug development, and improvement of cell cycle-targeted therapies. Many conventional microfluidic platforms isolate CTCs based on their size difference from other blood cells which renders them impractical for sorting overlapping-sized cells. To address this issue, we propose a method using a zigzag channel for continuous, label-free, and high throughput separation of CTCs coupling Dielectrophoresis (DEP) with inertial microfluidics. This hybrid channel exhibits enhanced similar-sized cell separation resolution and single-step retrieval of viable CTCs by combining inertial lift force, DEP force, and alternating curvature-induced Dean force. Through numerical investigation, separation of MDA-231 CTCs from identical-sized WBCs has been achieved at a relatively high Reynolds number of 125. Furthermore, the working parameters such as Reynolds number, voltage, and electrode configuration have been optimized for enhancing the separation efficiency. The proposed design can provide valuable insight into the development of a versatile, efficient, inexpensive, and novel platform with reduced analysis time for cancer diagnosis and prognosis.
{"title":"Circulating Tumor Cell Separation in a Zigzag Channel Using Dielectrophoresis Based Inertial Microfluidics","authors":"Md. Sadiqul Islam, M. R. Uddin, Xiaolin Chen","doi":"10.1115/imece2022-95384","DOIUrl":"https://doi.org/10.1115/imece2022-95384","url":null,"abstract":"\u0000 Circulating tumor cells (CTCs) are known to be a primary indicator of vital diagnostic and clinical information for early-stage cancer detection. Effective separation of CTCs from blood is crucial for genetic characterization of CTCs, drug development, and improvement of cell cycle-targeted therapies. Many conventional microfluidic platforms isolate CTCs based on their size difference from other blood cells which renders them impractical for sorting overlapping-sized cells. To address this issue, we propose a method using a zigzag channel for continuous, label-free, and high throughput separation of CTCs coupling Dielectrophoresis (DEP) with inertial microfluidics. This hybrid channel exhibits enhanced similar-sized cell separation resolution and single-step retrieval of viable CTCs by combining inertial lift force, DEP force, and alternating curvature-induced Dean force. Through numerical investigation, separation of MDA-231 CTCs from identical-sized WBCs has been achieved at a relatively high Reynolds number of 125. Furthermore, the working parameters such as Reynolds number, voltage, and electrode configuration have been optimized for enhancing the separation efficiency. The proposed design can provide valuable insight into the development of a versatile, efficient, inexpensive, and novel platform with reduced analysis time for cancer diagnosis and prognosis.","PeriodicalId":292222,"journal":{"name":"Volume 8: Fluids Engineering; Heat Transfer and Thermal Engineering","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116272220","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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