Abstract This study investigated the effect of the methanol–gasoline blend (M15) on the combustion and performance characteristics of a commercial light-duty Bharat Stage-VI (BS-VI) 2020 spark-ignition (SI) engine. The M15 and baseline gasoline (G100) engine tests were performed at a wide range of engine loads and speeds. For the M15 operation, it was ensured that the lambda values matched with the baseline gasoline operation at each engine operating point by changing fuel quantity manually. The combustion characteristics of M15 were quite similar to gasoline at all operating points. Alcohol addition improves octane number and flame speed, which changes the combustion characteristics of the engine, but in this study, the combustion characteristics of M15 fuel were almost identical. It may be due to blending a small fraction of methanol and the engine's high compression ratio, which improved the combustion kinetics. The coefficient of variance of indicated mean effective pressure was slightly lower for M15 than gasoline, except at 1000 rpm, where the charge mixing might not be adequate at low engine speed for M15 due to lower methanol volatility. Engine's brake thermal efficiency improved with M15 fueling by ∼1%, compared to baseline gasoline, though brake-specific fuel consumption deteriorated by ∼6% due to the lower calorific value of M15. Higher combustion stability and possibly lower heat transfer losses, as observed from slightly higher exhaust gas temperature (EGT), might have improved the engine's performance for M15. This study demonstrated that M15 fueling exhibited identical combustion characteristics and higher thermal efficiency than baseline gasoline fueling at similar lambda values in a commercial light-duty BS-VI SI engine.
{"title":"Combustion and Performance Evaluation of Methanol (M15)-Fueled BS-VI Compliant Light-Duty Spark-Ignition Engine","authors":"Ankur Kalwar, Rahul Kumar Singh, Ankit Gupta, Ranjeet Rajak, Gokul Gosakan, Avinash Kumar Agarwal","doi":"10.1115/1.4063343","DOIUrl":"https://doi.org/10.1115/1.4063343","url":null,"abstract":"Abstract This study investigated the effect of the methanol–gasoline blend (M15) on the combustion and performance characteristics of a commercial light-duty Bharat Stage-VI (BS-VI) 2020 spark-ignition (SI) engine. The M15 and baseline gasoline (G100) engine tests were performed at a wide range of engine loads and speeds. For the M15 operation, it was ensured that the lambda values matched with the baseline gasoline operation at each engine operating point by changing fuel quantity manually. The combustion characteristics of M15 were quite similar to gasoline at all operating points. Alcohol addition improves octane number and flame speed, which changes the combustion characteristics of the engine, but in this study, the combustion characteristics of M15 fuel were almost identical. It may be due to blending a small fraction of methanol and the engine's high compression ratio, which improved the combustion kinetics. The coefficient of variance of indicated mean effective pressure was slightly lower for M15 than gasoline, except at 1000 rpm, where the charge mixing might not be adequate at low engine speed for M15 due to lower methanol volatility. Engine's brake thermal efficiency improved with M15 fueling by ∼1%, compared to baseline gasoline, though brake-specific fuel consumption deteriorated by ∼6% due to the lower calorific value of M15. Higher combustion stability and possibly lower heat transfer losses, as observed from slightly higher exhaust gas temperature (EGT), might have improved the engine's performance for M15. This study demonstrated that M15 fueling exhibited identical combustion characteristics and higher thermal efficiency than baseline gasoline fueling at similar lambda values in a commercial light-duty BS-VI SI engine.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135793343","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 present study, the nonlinear thermal-magneto-mechanical stability and vibration of branched nanotube conveying nano-magnetic fluid embedded in linear and nonlinear elastic foundations are analyzed. The governing equations are established via Euler–Bernoulli theory, Hamilton’s principle, and the nonlocal theory of elasticity. The fluid flow and thermal behaviors of the nanofluid are described using modified Navier–Stokes and conservation of energy equations. With the aid of the Galerkin decomposition technique and differential transformation method (DTM), the coupled thermos-fluidic-vibration equation is solved analytically. The analytical solutions as presented in this study match with an existing experimental result and as such used to explore the influences of nonlocal parameters, downstream or branch angle, temperature, magnetic effect, fluid velocity, foundation parameters, and end conditions on vibrations of the nanotube. The results indicate that decreasing temperature change and augmenting the nanotube branch angle decreases the stability for the prebifurcation domain but increases for the post-bifurcation region. Furthermore, the magnetic term possesses a damping or an attenuating impact on the nanotube vibration response at any mode and for any boundary condition considered. It is anticipated that the outcome of this present study will find applications in the strategic optimization of designed nano-devices under thermo-mechanical flow-induced vibration.
{"title":"Nonlinear Thermal-Magneto-Mechanical Vibration Analysis of Single-Walled Embedded Branched Carbon Nanotubes Conveying Nanofluid","authors":"A. Yinusa, M. Sobamowo","doi":"10.1115/1.4062695","DOIUrl":"https://doi.org/10.1115/1.4062695","url":null,"abstract":"\u0000 In this present study, the nonlinear thermal-magneto-mechanical stability and vibration of branched nanotube conveying nano-magnetic fluid embedded in linear and nonlinear elastic foundations are analyzed. The governing equations are established via Euler–Bernoulli theory, Hamilton’s principle, and the nonlocal theory of elasticity. The fluid flow and thermal behaviors of the nanofluid are described using modified Navier–Stokes and conservation of energy equations. With the aid of the Galerkin decomposition technique and differential transformation method (DTM), the coupled thermos-fluidic-vibration equation is solved analytically. The analytical solutions as presented in this study match with an existing experimental result and as such used to explore the influences of nonlocal parameters, downstream or branch angle, temperature, magnetic effect, fluid velocity, foundation parameters, and end conditions on vibrations of the nanotube. The results indicate that decreasing temperature change and augmenting the nanotube branch angle decreases the stability for the prebifurcation domain but increases for the post-bifurcation region. Furthermore, the magnetic term possesses a damping or an attenuating impact on the nanotube vibration response at any mode and for any boundary condition considered. It is anticipated that the outcome of this present study will find applications in the strategic optimization of designed nano-devices under thermo-mechanical flow-induced vibration.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82203079","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}
M. Otto, L. Vesely, J. Kapat, Michael Stoia, Nicholas D. Applegate, Greg Natsui
Zero-emission aviation initiatives have mainly focused on using hydrogen or drop-in biofuels and sustainable aviation fuels (SAF) to replace fossil-based jet fuels to achieve near-term reductions in carbon emissions with minimal impacts on the global aircraft fleet and supporting infrastructure. Despite significant advances in the production of such fuels, scaling up manufacturing capability to be cost-competitive is an ongoing effort. This paper discusses ammonia as a near-zero-emission carrier of green hydrogen for aviation. Ammonia is proposed as a carrier of hydrogen fuel, a thermal sink for compressor intercooling, and cooling of cooling air, for NOx elimination, and for condensation of water vapor to reduce contrail formation. A two-pronged investigation is presented, where first, a holistic discussion on alternative fuels identifies ammonia as a suitable hydrogen carrier for aviation. Second, the implications and potentials of ammonia are discussed and analyzed at the airframe and engine system level. Stemming from the already established fertilizer industry, a robust supply chain for ammonia exists together with experience in handling large quantities of the fluid despite its higher toxicity compared to hydrogen and other alternative aviation fuels of the future. It is found that ammonia requires significantly less water than SAF in production, on par with hydrogen, at comparable life cycle emission levels. The feasibility of heat exchangers for compressor intercooling and turbine-cooled cooling air, enabled by ammonia’s non-coking properties, is demonstrated, and paves the way toward efficient zero-emission engine cores.
{"title":"Ammonia as an Aircraft Fuel: A Critical Assessment From Airport to Wake","authors":"M. Otto, L. Vesely, J. Kapat, Michael Stoia, Nicholas D. Applegate, Greg Natsui","doi":"10.1115/1.4062626","DOIUrl":"https://doi.org/10.1115/1.4062626","url":null,"abstract":"\u0000 Zero-emission aviation initiatives have mainly focused on using hydrogen or drop-in biofuels and sustainable aviation fuels (SAF) to replace fossil-based jet fuels to achieve near-term reductions in carbon emissions with minimal impacts on the global aircraft fleet and supporting infrastructure. Despite significant advances in the production of such fuels, scaling up manufacturing capability to be cost-competitive is an ongoing effort. This paper discusses ammonia as a near-zero-emission carrier of green hydrogen for aviation. Ammonia is proposed as a carrier of hydrogen fuel, a thermal sink for compressor intercooling, and cooling of cooling air, for NOx elimination, and for condensation of water vapor to reduce contrail formation. A two-pronged investigation is presented, where first, a holistic discussion on alternative fuels identifies ammonia as a suitable hydrogen carrier for aviation. Second, the implications and potentials of ammonia are discussed and analyzed at the airframe and engine system level. Stemming from the already established fertilizer industry, a robust supply chain for ammonia exists together with experience in handling large quantities of the fluid despite its higher toxicity compared to hydrogen and other alternative aviation fuels of the future. It is found that ammonia requires significantly less water than SAF in production, on par with hydrogen, at comparable life cycle emission levels. The feasibility of heat exchangers for compressor intercooling and turbine-cooled cooling air, enabled by ammonia’s non-coking properties, is demonstrated, and paves the way toward efficient zero-emission engine cores.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85889683","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}
T. Draper, A. Gunnarsson, Andrew Fry, K. Andersson, T. Ring, E. Eddings
This work evaluates and compares radiative heat transfer measurements conducted at the 471−MWE Hunter Power Plant Unit 3 utility boiler in Utah, United States, during standard operation with coal and also co-firing with biomass. The coal used was a Utah-sourced bituminous coal, which was mixed with torrefied wood (15% by weight) for the co-firing test. Radiation from the flame was measured using radiometers of three different designs. Data were gathered at three elevations along the boiler wall. Overall, the measured heat fluxes and corresponding temporal variations decreased with increasing boiler elevation. While the variation in the replicates of the heat flux data is notable, a statistical analysis indicates that the heat flux profile at the elevations investigated is not significantly affected by the change in fuel.
{"title":"A Comparison of Industrial-Scale Radiometer Heat Flux Measurements Between Pulverized-Coal and Coal/Biomass Co-Firing Combustion","authors":"T. Draper, A. Gunnarsson, Andrew Fry, K. Andersson, T. Ring, E. Eddings","doi":"10.1115/1.4056537","DOIUrl":"https://doi.org/10.1115/1.4056537","url":null,"abstract":"\u0000 This work evaluates and compares radiative heat transfer measurements conducted at the 471−MWE Hunter Power Plant Unit 3 utility boiler in Utah, United States, during standard operation with coal and also co-firing with biomass. The coal used was a Utah-sourced bituminous coal, which was mixed with torrefied wood (15% by weight) for the co-firing test. Radiation from the flame was measured using radiometers of three different designs. Data were gathered at three elevations along the boiler wall. Overall, the measured heat fluxes and corresponding temporal variations decreased with increasing boiler elevation. While the variation in the replicates of the heat flux data is notable, a statistical analysis indicates that the heat flux profile at the elevations investigated is not significantly affected by the change in fuel.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88548195","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}
The present study aims to assess the potential of the neural ordinary differential equations (NODE) network for reliable and computationally efficient implementation of chemistry in combustion simulations. Investigations are performed using a hydrogen-air pairwise mixing stirred reactor (PMSR). The PMSR is a zero-dimensional case affordable to study combustion chemistry entailing a similar numerical solution procedure as probability density function methods for turbulent combustion simulations. A systematic approach is presented to apply the NODE, solely trained on canonical constant pressure homogeneous reactor data, to predict complex chemistry and mixing interactions in PMSR. The reactor involves combustion of hydrogen in air described by a finite-rate mechanism with 9 chemical species and 21 reaction steps. The NODE network is shown to accurately capture the evolution of thermochemical variables for different mixing and chemical timescales. It also exhibits a significant reduction in numerical stiffness resulting in improving the computational efficiency and enabling the use of explicit solvers for the integration of chemical kinetics. The assessment results based on PMSR show that compared to direct integration of detailed kinetics, the NODE can achieve significant computational time speedup for a comparable accuracy.
{"title":"Performance Assessment of Chemical Kinetics Neural Ordinary Differential Equations in Pairwise Mixing Stirred Reactor","authors":"S. Bansude, Farhad Imani, R. Sheikhi","doi":"10.1115/1.4056476","DOIUrl":"https://doi.org/10.1115/1.4056476","url":null,"abstract":"\u0000 The present study aims to assess the potential of the neural ordinary differential equations (NODE) network for reliable and computationally efficient implementation of chemistry in combustion simulations. Investigations are performed using a hydrogen-air pairwise mixing stirred reactor (PMSR). The PMSR is a zero-dimensional case affordable to study combustion chemistry entailing a similar numerical solution procedure as probability density function methods for turbulent combustion simulations. A systematic approach is presented to apply the NODE, solely trained on canonical constant pressure homogeneous reactor data, to predict complex chemistry and mixing interactions in PMSR. The reactor involves combustion of hydrogen in air described by a finite-rate mechanism with 9 chemical species and 21 reaction steps. The NODE network is shown to accurately capture the evolution of thermochemical variables for different mixing and chemical timescales. It also exhibits a significant reduction in numerical stiffness resulting in improving the computational efficiency and enabling the use of explicit solvers for the integration of chemical kinetics. The assessment results based on PMSR show that compared to direct integration of detailed kinetics, the NODE can achieve significant computational time speedup for a comparable accuracy.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88674492","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 Combustion in dimethyl-ether (DME)-fueled engines needs to be assessed carefully for its widespread acceptability from a drivability viewpoint. Since the test engine used in an off-highway segment, it was tested in a steady-state cycle for engine performance, combustion, emissions, and their cyclic variations, which were the only parameters to assess the drivability. This study investigated and analyzed the cyclic variations of a 100% DME-fueled engine equipped with modified mechanical fuel injection equipment. It was compared with baseline diesel to understand its positive and negative aspects. Experiments were conducted at different engine speeds (1200,1600, and 2000 rpm) and loads (No Load, 1.29, 2.59, 3.88, 5.18, and 6.47 bar brake mean effective pressure (BMEP)) . In-cylinder pressure was recorded for 250 consecutive engine cycles, and many combustion parameters were comparatively analyzed for diesel and DME fuelings. The coefficient of variation (COV) of maximum in-cylinder pressure (Pmax) was lower for DME than diesel at 1600 rpm and comparable at the other remaining engine speeds (1200 and 2000 rpm). Variations in COV of Pmax were higher at low loads and negligible at high loads for both test fuels. At 2000 rpm, the crank angle positions at which Pmax occurred were distributed in a narrow range for DME, representing higher combustion stability than baseline diesel. Variations in the maximum rate of pressure rise (RoPRmax) were lower for DME at 3.88 and 6.47 bar BMEP, while these were higher at 1.29 bar BMEP than baseline diesel. COV of indicated mean effective pressure (COVIMEP) decreased from lower to higher loads for diesel and DME fueling at 1600 and 2000 rpm engine speeds. The differences in COVIMEP between diesel and DME were negligible at higher loads, representing engine stability similar to baseline diesel. Combustion parameters assessed indicated that DME fueling led to lower cyclic variations than baseline diesel as the engine operated from lower to higher loads. At lower loads, DME fueling showed higher cyclic variations than baseline diesel.
摘要二甲醚(DME)燃料发动机的燃烧需要从驾驶性能的角度对其广泛的可接受性进行仔细的评估。由于测试发动机用于非公路路段，因此在稳态循环中测试了发动机性能，燃烧，排放及其循环变化，这些是评估驾驶性能的唯一参数。本文研究并分析了安装改进的机械燃油喷射装置的100%二甲醚燃料发动机的循环变化。将其与基线柴油进行比较，以了解其积极和消极方面。在不同发动机转速(1200、1600和2000 rpm)和负载(空载、1.29、2.59、3.88、5.18和6.47 bar制动平均有效压力(BMEP))下进行了实验。记录了250个连续发动机循环的缸内压力，并对柴油和二甲醚燃料的许多燃烧参数进行了比较分析。DME发动机最大缸内压力(Pmax)的变异系数(COV)在1600 rpm时低于柴油发动机，在其他发动机转速(1200和2000 rpm)下也相当。两种试验燃料的Pmax COV在低负荷时变化较大，在高负荷时变化可以忽略不计。在2000 rpm时，DME出现Pmax的曲柄角位置分布在一个较窄的范围内，表现出比基线柴油更高的燃烧稳定性。DME在3.88和6.47 bar BMEP时最大压力上升率(RoPRmax)的变化较低，而在1.29 bar BMEP时，这些变化高于基线柴油。在1600转/分和2000转/分的发动机转速下，柴油和二甲醚加油时，指示平均有效压力(COVIMEP)的COV从低负荷到高负荷下降。在更高的负载下，柴油和二甲醚的COVIMEP差异可以忽略不计，这表明发动机的稳定性与基线柴油相似。燃烧参数评估表明，当发动机从低负荷到高负荷运行时，DME燃料比基线柴油的循环变化更小。在较低负荷下，DME加注比基线柴油表现出更高的循环变化。
{"title":"Cyclic Combustion Variability of Dimethyl-Ether-Fueled Agricultural Tractor Engine","authors":"Avinash Kumar Agarwal, Hardikk Valera, Vikram Kumar, Nalini Kanta Mukherjee, Shanti Mehra, Devendra Nene","doi":"10.1115/1.4063201","DOIUrl":"https://doi.org/10.1115/1.4063201","url":null,"abstract":"Abstract Combustion in dimethyl-ether (DME)-fueled engines needs to be assessed carefully for its widespread acceptability from a drivability viewpoint. Since the test engine used in an off-highway segment, it was tested in a steady-state cycle for engine performance, combustion, emissions, and their cyclic variations, which were the only parameters to assess the drivability. This study investigated and analyzed the cyclic variations of a 100% DME-fueled engine equipped with modified mechanical fuel injection equipment. It was compared with baseline diesel to understand its positive and negative aspects. Experiments were conducted at different engine speeds (1200,1600, and 2000 rpm) and loads (No Load, 1.29, 2.59, 3.88, 5.18, and 6.47 bar brake mean effective pressure (BMEP)) . In-cylinder pressure was recorded for 250 consecutive engine cycles, and many combustion parameters were comparatively analyzed for diesel and DME fuelings. The coefficient of variation (COV) of maximum in-cylinder pressure (Pmax) was lower for DME than diesel at 1600 rpm and comparable at the other remaining engine speeds (1200 and 2000 rpm). Variations in COV of Pmax were higher at low loads and negligible at high loads for both test fuels. At 2000 rpm, the crank angle positions at which Pmax occurred were distributed in a narrow range for DME, representing higher combustion stability than baseline diesel. Variations in the maximum rate of pressure rise (RoPRmax) were lower for DME at 3.88 and 6.47 bar BMEP, while these were higher at 1.29 bar BMEP than baseline diesel. COV of indicated mean effective pressure (COVIMEP) decreased from lower to higher loads for diesel and DME fueling at 1600 and 2000 rpm engine speeds. The differences in COVIMEP between diesel and DME were negligible at higher loads, representing engine stability similar to baseline diesel. Combustion parameters assessed indicated that DME fueling led to lower cyclic variations than baseline diesel as the engine operated from lower to higher loads. At lower loads, DME fueling showed higher cyclic variations than baseline diesel.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135784240","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 In this paper, the performance of R744 and R744/R170 mixed refrigerants in refrigeration and air source heat pump systems is studied by the simulation method. The change trend of coefficient of performance (COP), refrigeration/heat capacity, power consumption with discharge pressure, and the ratio of R744 is analyzed. In addition, optimal parameters of the system are discussed in detail with the change of evaporation temperature, outlet temperature of the gas cooler, and different proportions of R744. The results show that when the discharge pressure is 8–12 MPa, there is a critical ratio of R744. When the ratio of R744 is less than the critical ratio, the optimal pressure of the system increases with the increase of the ratio of R744, and when the ratio of R744 is higher than critical ratio, the optimal pressure of the system decreases with the increase of the ratio of R744. The change trend of COP with the ratio of R744 is first decreasing and then increasing, the optimal discharge temperature of the system increases with the increase of the ratio of R744, and the change trend of optimal discharge pressure with the ratio of R744 is first increasing and then decreasing. In addition, when the evaporation temperature is 233–253 K and the gas cooler outlet temperature is 308–318 K, the average optimal pressure and temperature of R744/R170 (25/75) are 11.64% and 8.06% lower than R744, respectively. And it is the most suitable refrigerant to replace R744. Finally, the optimal performance parameter correlations of R744, R744/R170 (25/75), R744/R170 (50/50), and R744/R170 (77.6/22.4) under the given conditions are fitted through the simulation data.
{"title":"Comprehensive Performance Analysis and Correlation Fitting of R744 and Its Mixture Used in Refrigeration and Heat Pump Systems","authors":"Dahan Sun, Zhongyan Liu, Hao Zhang, Xin Zhang","doi":"10.1115/1.4063341","DOIUrl":"https://doi.org/10.1115/1.4063341","url":null,"abstract":"Abstract In this paper, the performance of R744 and R744/R170 mixed refrigerants in refrigeration and air source heat pump systems is studied by the simulation method. The change trend of coefficient of performance (COP), refrigeration/heat capacity, power consumption with discharge pressure, and the ratio of R744 is analyzed. In addition, optimal parameters of the system are discussed in detail with the change of evaporation temperature, outlet temperature of the gas cooler, and different proportions of R744. The results show that when the discharge pressure is 8–12 MPa, there is a critical ratio of R744. When the ratio of R744 is less than the critical ratio, the optimal pressure of the system increases with the increase of the ratio of R744, and when the ratio of R744 is higher than critical ratio, the optimal pressure of the system decreases with the increase of the ratio of R744. The change trend of COP with the ratio of R744 is first decreasing and then increasing, the optimal discharge temperature of the system increases with the increase of the ratio of R744, and the change trend of optimal discharge pressure with the ratio of R744 is first increasing and then decreasing. In addition, when the evaporation temperature is 233–253 K and the gas cooler outlet temperature is 308–318 K, the average optimal pressure and temperature of R744/R170 (25/75) are 11.64% and 8.06% lower than R744, respectively. And it is the most suitable refrigerant to replace R744. Finally, the optimal performance parameter correlations of R744, R744/R170 (25/75), R744/R170 (50/50), and R744/R170 (77.6/22.4) under the given conditions are fitted through the simulation data.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135793554","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}
A numerical study has been carried out on the two-dimensional flow past a circular cylinder. In this case, a splitter plate is provided at the rear stagnation point in the downstream direction. ansys fluent has been used to carry out the numerical simulations based on finite volume method approach. Grid independence was achieved and the numerical model was validated with results available in open literature at Reynolds numbers of 100, 5000, and 100,000 respectively. In the present investigation, the characteristics of vortex shedding due to the presence of splitter plate in the circular cylinder were investigated. The main focus of this research was to find the optimal splitter plate length for low, moderate, and high Reynolds numbers. It was observed that at low, moderate, and high Reynolds numbers, the drag coefficient (cd) for optimal plate length decreased drastically as compared to the baseline circular cylinder case. Moreover, the fluctuating nature of lift coefficient (cl) had also ceased. This research work has a good potential to decrease time-varying structural loads on bluff bodies by decreasing the vortex shedding frequency and consequently decreasing drag. The scope of our research extends to structures of bridges and large vehicles, radiator pipes of heat exchangers, landing gears of aircraft, and many more.
{"title":"Drag Reduction for Flow Past Circular Cylinder Using Static Extended Trailing Edge","authors":"Ayush Boral, Souvik Dutta, Anwesha Das, Ankit Kumar, Nilotpala Bej, Pooja Chaubdar, Biranchi Narayana Das, A. Harichandan","doi":"10.1115/1.4057009","DOIUrl":"https://doi.org/10.1115/1.4057009","url":null,"abstract":"\u0000 A numerical study has been carried out on the two-dimensional flow past a circular cylinder. In this case, a splitter plate is provided at the rear stagnation point in the downstream direction. ansys fluent has been used to carry out the numerical simulations based on finite volume method approach. Grid independence was achieved and the numerical model was validated with results available in open literature at Reynolds numbers of 100, 5000, and 100,000 respectively. In the present investigation, the characteristics of vortex shedding due to the presence of splitter plate in the circular cylinder were investigated. The main focus of this research was to find the optimal splitter plate length for low, moderate, and high Reynolds numbers. It was observed that at low, moderate, and high Reynolds numbers, the drag coefficient (cd) for optimal plate length decreased drastically as compared to the baseline circular cylinder case. Moreover, the fluctuating nature of lift coefficient (cl) had also ceased. This research work has a good potential to decrease time-varying structural loads on bluff bodies by decreasing the vortex shedding frequency and consequently decreasing drag. The scope of our research extends to structures of bridges and large vehicles, radiator pipes of heat exchangers, landing gears of aircraft, and many more.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80961518","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}
This paper assesses the validity of the Two-Step, One-Way (TSOW) coupled method for computational fluid dynamics, which splits a complicated geometry into an upstream and a downstream part. The problem is solved in two steps: first, the upstream part using approximate downstream boundary conditions, followed by a solution of the downstream flow where the inlet boundary conditions are extracted from the upstream solution. The method is based on two assumptions: first, the solution for the upstream part should be identical in the common domain to a complete solution. Second, the solution for the downstream part should be identical in the common domain to a complete solution. The resulting agreement between the upstream solution and the full solution was excellent, except in the vicinity of the outflow boundary. For the assessment of the second assumption, the downstream flow was simulated with two sets of boundary conditions, one that was extracted from the full simulation, and one that came from the upstream part solution. The two solutions in the downstream geometry with slightly different boundary conditions agreed excellently with each other but exhibited small differences from the full solution. Overall, the difference to the full solution is judged to be acceptable for many engineering design situations. The solution time for the TSOW method was about 23 h faster than the full solution, which took about 85 h on the same hardware. For additional design iterations, where the same upstream geometry can be used, a 30-h gain would be obtained for each step.
{"title":"Systematic Assessment of the Two-Step, One-Way Coupled Method for Computational Fluid Dynamics","authors":"N. Papafilippou, M. A. Chishty, R. Gebart","doi":"10.1115/1.4062111","DOIUrl":"https://doi.org/10.1115/1.4062111","url":null,"abstract":"\u0000 This paper assesses the validity of the Two-Step, One-Way (TSOW) coupled method for computational fluid dynamics, which splits a complicated geometry into an upstream and a downstream part. The problem is solved in two steps: first, the upstream part using approximate downstream boundary conditions, followed by a solution of the downstream flow where the inlet boundary conditions are extracted from the upstream solution. The method is based on two assumptions: first, the solution for the upstream part should be identical in the common domain to a complete solution. Second, the solution for the downstream part should be identical in the common domain to a complete solution. The resulting agreement between the upstream solution and the full solution was excellent, except in the vicinity of the outflow boundary. For the assessment of the second assumption, the downstream flow was simulated with two sets of boundary conditions, one that was extracted from the full simulation, and one that came from the upstream part solution. The two solutions in the downstream geometry with slightly different boundary conditions agreed excellently with each other but exhibited small differences from the full solution. Overall, the difference to the full solution is judged to be acceptable for many engineering design situations. The solution time for the TSOW method was about 23 h faster than the full solution, which took about 85 h on the same hardware. For additional design iterations, where the same upstream geometry can be used, a 30-h gain would be obtained for each step.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80877181","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}
This research first presents a method of peel testing developed by the researchers to characterize the strength of the interface between fabric and additively manufactured material. Experimentation is next presented that characterizes the interfacial strength relative to a set of parameters which include fabric fiber morphology, thickness of sizing applied to fabric, 3D printer bed temperature, and angle of additive manufacturing relative to the fabric warp direction. The interface strength within the parameter space presented was then searched and found to have a maximum of 5.18 N/mm using a novel set of parameters. This interface strength indicates the method of additive manufacturing direction on fabric may be suitable for use in a broader range of applications than previously proven feasible. Relatively rough, thick, and loose weave fabrics were found to promote interface strength compared to smoother, thinner, and finer woven fabrics. Relatively higher bed temperatures also promoted higher interface strength. Sizings on the fabric were found to promote interface strength with relatively smooth, thin, or fine fabrics which do not themselves promote high mechanical interlocking. Using these research findings, interface strength between fabric and additively manufactured material can be modified to suit the application.
{"title":"Investigation of the Interfacial Adhesion Strength of Parts Additively Manufactured on Fabrics","authors":"Maxwell Blais, Scott M Tomlinson, Bashir Khoda","doi":"10.1115/1.4062281","DOIUrl":"https://doi.org/10.1115/1.4062281","url":null,"abstract":"\u0000 This research first presents a method of peel testing developed by the researchers to characterize the strength of the interface between fabric and additively manufactured material. Experimentation is next presented that characterizes the interfacial strength relative to a set of parameters which include fabric fiber morphology, thickness of sizing applied to fabric, 3D printer bed temperature, and angle of additive manufacturing relative to the fabric warp direction. The interface strength within the parameter space presented was then searched and found to have a maximum of 5.18 N/mm using a novel set of parameters. This interface strength indicates the method of additive manufacturing direction on fabric may be suitable for use in a broader range of applications than previously proven feasible. Relatively rough, thick, and loose weave fabrics were found to promote interface strength compared to smoother, thinner, and finer woven fabrics. Relatively higher bed temperatures also promoted higher interface strength. Sizings on the fabric were found to promote interface strength with relatively smooth, thin, or fine fabrics which do not themselves promote high mechanical interlocking. Using these research findings, interface strength between fabric and additively manufactured material can be modified to suit the application.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73683922","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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