Xiaojie Zhao, Kai Zhao, Xuan Zhang, Yang Gao, He Liu
Abstract Based on the principle of cyclone separation and 3D printing technology, a novel variable pitch hydrocyclone structure was proposed for the axial flow hydrocyclone separators of oil wells. The structural parameters of this variable pitch hydrocyclone were optimized via a combined approach of the Plackett-Burman design, response surface design and computational fluid dynamics. A quadratic polynomial mathematical relationship between significant structural parameters and separation efficiency was established. The effects of the inlet flow rate, split ratio and oil phase volume fraction on oil-water separation performance were systematically analyzed. A laboratory test system for oil-water swirl separation was constructed to verify the accuracy of numerical simulation results and the efficiency of the optimized structure. The optimal overflow split ratio, inlet flow rate and oil concentration for the hydrocyclone are 30%,96 m3/d and 2%, respectively. The combination of these optimal parameters results in an experimental separation efficiency of 99.38%, which is higher than that of the conventional structure. The experimental results are in good agreement with the simulation results.
{"title":"Structure optimization and performance evaluation of downhole oil-water separation tools: a novel hydrocyclone","authors":"Xiaojie Zhao, Kai Zhao, Xuan Zhang, Yang Gao, He Liu","doi":"10.1115/1.4064001","DOIUrl":"https://doi.org/10.1115/1.4064001","url":null,"abstract":"Abstract Based on the principle of cyclone separation and 3D printing technology, a novel variable pitch hydrocyclone structure was proposed for the axial flow hydrocyclone separators of oil wells. The structural parameters of this variable pitch hydrocyclone were optimized via a combined approach of the Plackett-Burman design, response surface design and computational fluid dynamics. A quadratic polynomial mathematical relationship between significant structural parameters and separation efficiency was established. The effects of the inlet flow rate, split ratio and oil phase volume fraction on oil-water separation performance were systematically analyzed. A laboratory test system for oil-water swirl separation was constructed to verify the accuracy of numerical simulation results and the efficiency of the optimized structure. The optimal overflow split ratio, inlet flow rate and oil concentration for the hydrocyclone are 30%,96 m3/d and 2%, respectively. The combination of these optimal parameters results in an experimental separation efficiency of 99.38%, which is higher than that of the conventional structure. The experimental results are in good agreement with the simulation results.","PeriodicalId":15676,"journal":{"name":"Journal of Energy Resources Technology-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135474762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Guo Chen, Pengxiang Diwu, Zhao Wenqi, Wu Xuelin, Wang Yong, Guan Yuqi, Abal-hassan F.S.A Djamalillail, Li Junjian
Abstract Fracture-pore carbonate reservoirs exhibit strong microscopic heterogeneity and complex seepage characteristics, resulting in suboptimal oil drive efficiency and development outcomes. Moreover, water channeling is often a serious problem in the development of fractured porous carbonate rocks, and the blockage of degassed bubbles in the throat is one of the reasons that cannot be ignored. In order to reveal the degree of influence of bubbles on waterflood sweep, this paper employs microfluidic technology to design three distinct chips, namely fracture-type, composite-type, and cave-type, to visually illustrate the influence of the gas phase on three-phase flow. A quantification method is established to analyze the variation characteristics of pore diameter utilization ratio in different types of carbonate reservoirs. Compared with water flooding experiments without the gas phase, the recovery factor of water flooding with the presence of the gas phase decreases by 0.6,3.4, and 15.3 percentage points for three distinct chips, respectively. In fracture-type reservoirs, the main focus is on sealing the primary fracture seepage channel and mitigating the shielding effect of the gas phase on matrix utilization. For composite-type reservoirs, the primary objective is to seal fractures and eliminate the shielding effect of the gas phase. In cave-type reservoirs, the primary goal is to eliminate the sealing effect caused by the discontinuous gas phase within small pore throats.
{"title":"Effects of Trapped Gas in Fracture-Pore Carbonate Reservoirs","authors":"Guo Chen, Pengxiang Diwu, Zhao Wenqi, Wu Xuelin, Wang Yong, Guan Yuqi, Abal-hassan F.S.A Djamalillail, Li Junjian","doi":"10.1115/1.4063931","DOIUrl":"https://doi.org/10.1115/1.4063931","url":null,"abstract":"Abstract Fracture-pore carbonate reservoirs exhibit strong microscopic heterogeneity and complex seepage characteristics, resulting in suboptimal oil drive efficiency and development outcomes. Moreover, water channeling is often a serious problem in the development of fractured porous carbonate rocks, and the blockage of degassed bubbles in the throat is one of the reasons that cannot be ignored. In order to reveal the degree of influence of bubbles on waterflood sweep, this paper employs microfluidic technology to design three distinct chips, namely fracture-type, composite-type, and cave-type, to visually illustrate the influence of the gas phase on three-phase flow. A quantification method is established to analyze the variation characteristics of pore diameter utilization ratio in different types of carbonate reservoirs. Compared with water flooding experiments without the gas phase, the recovery factor of water flooding with the presence of the gas phase decreases by 0.6,3.4, and 15.3 percentage points for three distinct chips, respectively. In fracture-type reservoirs, the main focus is on sealing the primary fracture seepage channel and mitigating the shielding effect of the gas phase on matrix utilization. For composite-type reservoirs, the primary objective is to seal fractures and eliminate the shielding effect of the gas phase. In cave-type reservoirs, the primary goal is to eliminate the sealing effect caused by the discontinuous gas phase within small pore throats.","PeriodicalId":15676,"journal":{"name":"Journal of Energy Resources Technology-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135539438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Vehicle fuel evaporative emissions are an important source of volatile organic compounds (VOCs), causing serious pollution to the environment. Plug-in hybrid electric vehicles (PHEVs) often use high-pressure fuel tank to seal the fuel vapor generated by running loss (RL), hot soak loss (HSL) and diurnal breathing loss (DBL) in the fuel tank, resulting in increased refueling emissions. With the widespread use of PHEVs, the issue of refueling emissions cannot be ignored. In this study, according to the working characteristics of PHEV, the refueling process is divided into depressurization phase and refueling phase, and a mathematical model is established for the fuel vapor emission process. The mathematical model is solved and calculated by using MATLAB, and compared with the experimental results. The error between experimental and calculated results of refueling emissions is only 2.45%, indicating that the established mathematical model can accurately predict the refueling emissions of PHEVs. The refueling emission experiment activities is carried out, and the influencing factors of PHEV refueling emission are discussed, including initial pressure, ambient temperature and refueling temperature. The effect of the temperature difference between ambient temperature and refueling temperature on refueling emissions is discussed for the first time, and it is found that refueling temperature has a more significant impact on refueling emissions compared with ambient temperature. When refueling temperature increases to 303 K and 313 K compared to 293 K, refueling emission mass increases by 31.97% and 69.88% respectively.
{"title":"Modeling and influence factors analysis of refueling emissions for plug-in hybrid electric vehicles","authors":"Xudong Wu, Ren He","doi":"10.1115/1.4064002","DOIUrl":"https://doi.org/10.1115/1.4064002","url":null,"abstract":"Abstract Vehicle fuel evaporative emissions are an important source of volatile organic compounds (VOCs), causing serious pollution to the environment. Plug-in hybrid electric vehicles (PHEVs) often use high-pressure fuel tank to seal the fuel vapor generated by running loss (RL), hot soak loss (HSL) and diurnal breathing loss (DBL) in the fuel tank, resulting in increased refueling emissions. With the widespread use of PHEVs, the issue of refueling emissions cannot be ignored. In this study, according to the working characteristics of PHEV, the refueling process is divided into depressurization phase and refueling phase, and a mathematical model is established for the fuel vapor emission process. The mathematical model is solved and calculated by using MATLAB, and compared with the experimental results. The error between experimental and calculated results of refueling emissions is only 2.45%, indicating that the established mathematical model can accurately predict the refueling emissions of PHEVs. The refueling emission experiment activities is carried out, and the influencing factors of PHEV refueling emission are discussed, including initial pressure, ambient temperature and refueling temperature. The effect of the temperature difference between ambient temperature and refueling temperature on refueling emissions is discussed for the first time, and it is found that refueling temperature has a more significant impact on refueling emissions compared with ambient temperature. When refueling temperature increases to 303 K and 313 K compared to 293 K, refueling emission mass increases by 31.97% and 69.88% respectively.","PeriodicalId":15676,"journal":{"name":"Journal of Energy Resources Technology-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135474617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Guoqing Zhang, Zhijun Zhou, Chunxue Cui, Jian Zhang, Jingyi Wang
Abstract With the growing significance of shale oil in the realm of oil and gas resources, there has been a heightened focus on the impact of the indeterminate oil-water two-phase flow behaviour in shale reservoirs on the effective exploitation of shale oil. The utilization of FIB-SEM scanning on shale samples enables the establishment of the real pore network structure and facilitates the analysis of pore type, pore throat size and connectivity of shale reservoirs through the implementation of two-dimensional slices. Subsequently, the gridded connectivity-based pore network model is utilized to conduct oil-water two-phase flow simulation, wherein the L-S and N-S mathematical models are incorporated to quantitatively examine the correlation between the displacement pressure and wettability and the recovery degree and remaining oil, as well as the impact of throat size on pressure loss. The research findings indicate the emergence of five distinctive pore types in shale reservoirs, namely intergranular pores, dissolution pores, intercrystalline pores, intracrystalline pores, and micro-fractures. In shale reservoirs with poor connectivity, a significant quantity of nanometer-scale pores are generated, wherein the seepage capacity is primarily influenced by the size and connectivity of pore throats. The smaller the throat size is, the greater the displacement pressure will be and the greater the pressure drop will be after the throat is passed through. To prevent fingering and excessive pressure drop, it is necessary to maintain reasonable control over the displacement pressure. The displacement efficiency is optimal when the wall surface is in a water-wet state. Therefore, enhancing the wettability of the surface can facilitate the efficient recovery of the remaining oil in the microscopic pore throats. The research findings offer valuable theoretical insights for the efficient exploitation of shale oil resources.
{"title":"Shale Oil-water Two-phase Flow Simulation based on Pore Network Modeling","authors":"Guoqing Zhang, Zhijun Zhou, Chunxue Cui, Jian Zhang, Jingyi Wang","doi":"10.1115/1.4063999","DOIUrl":"https://doi.org/10.1115/1.4063999","url":null,"abstract":"Abstract With the growing significance of shale oil in the realm of oil and gas resources, there has been a heightened focus on the impact of the indeterminate oil-water two-phase flow behaviour in shale reservoirs on the effective exploitation of shale oil. The utilization of FIB-SEM scanning on shale samples enables the establishment of the real pore network structure and facilitates the analysis of pore type, pore throat size and connectivity of shale reservoirs through the implementation of two-dimensional slices. Subsequently, the gridded connectivity-based pore network model is utilized to conduct oil-water two-phase flow simulation, wherein the L-S and N-S mathematical models are incorporated to quantitatively examine the correlation between the displacement pressure and wettability and the recovery degree and remaining oil, as well as the impact of throat size on pressure loss. The research findings indicate the emergence of five distinctive pore types in shale reservoirs, namely intergranular pores, dissolution pores, intercrystalline pores, intracrystalline pores, and micro-fractures. In shale reservoirs with poor connectivity, a significant quantity of nanometer-scale pores are generated, wherein the seepage capacity is primarily influenced by the size and connectivity of pore throats. The smaller the throat size is, the greater the displacement pressure will be and the greater the pressure drop will be after the throat is passed through. To prevent fingering and excessive pressure drop, it is necessary to maintain reasonable control over the displacement pressure. The displacement efficiency is optimal when the wall surface is in a water-wet state. Therefore, enhancing the wettability of the surface can facilitate the efficient recovery of the remaining oil in the microscopic pore throats. The research findings offer valuable theoretical insights for the efficient exploitation of shale oil resources.","PeriodicalId":15676,"journal":{"name":"Journal of Energy Resources Technology-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135584756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K A Srinivasa Raghavan, S Srinivasa Rao, V R K Raju
Abstract Flame tip-opening in a micro-combustor with a controlled centrally slotted bluff body adversely affects the combustion characteristics, leading to reduced average combustion efficiency and exhaust gas temperature. To minimize the adverse effects of the flame tip-opening, a deflector is introduced in the micro-combustor, downstream to the bluff body, and its effect on various combustion parameters is studied. The insertion of a deflector significantly increases the exhaust gas temperatures in the central region by establishing a secondary flame root. However, sudden changes in the flow direction caused by the insertion of deflector induce a sudden expansion-compression strain on the flame front, thereby slightly reducing the temperature of the flame zones on either side of the central region. A downstream shift in the position of the deflector marginally mitigates the adverse effects of sudden expansion compression strain on the exhaust gas temperature, as they are induced within the secondary reaction flame zones. On the other hand, the downstream shift of the deflector negatively impacts the exhaust gas temperature in the central region due to the reduced length available for near-complete combustion downstream of the secondary flame root. In conclusion, the deflector positioned farther from the outlet is found to result in better overall combustion characteristics at higher controllable flow ratios.
{"title":"Effect of Deflector on the Combustion Characteristics of a Micro-Combustor with a Controlled Centrally Slotted Bluff Body","authors":"K A Srinivasa Raghavan, S Srinivasa Rao, V R K Raju","doi":"10.1115/1.4063932","DOIUrl":"https://doi.org/10.1115/1.4063932","url":null,"abstract":"Abstract Flame tip-opening in a micro-combustor with a controlled centrally slotted bluff body adversely affects the combustion characteristics, leading to reduced average combustion efficiency and exhaust gas temperature. To minimize the adverse effects of the flame tip-opening, a deflector is introduced in the micro-combustor, downstream to the bluff body, and its effect on various combustion parameters is studied. The insertion of a deflector significantly increases the exhaust gas temperatures in the central region by establishing a secondary flame root. However, sudden changes in the flow direction caused by the insertion of deflector induce a sudden expansion-compression strain on the flame front, thereby slightly reducing the temperature of the flame zones on either side of the central region. A downstream shift in the position of the deflector marginally mitigates the adverse effects of sudden expansion compression strain on the exhaust gas temperature, as they are induced within the secondary reaction flame zones. On the other hand, the downstream shift of the deflector negatively impacts the exhaust gas temperature in the central region due to the reduced length available for near-complete combustion downstream of the secondary flame root. In conclusion, the deflector positioned farther from the outlet is found to result in better overall combustion characteristics at higher controllable flow ratios.","PeriodicalId":15676,"journal":{"name":"Journal of Energy Resources Technology-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136317585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The main objective of this study is to carry out the thermodynamic analysis of a new power/ refrigeration combined cycle which consists of an ejector refrigeration cycle (ERC) and a Kalina cycle. In ERC, nanorefrigerants are used as the working fluid. Used nanorefrigerants are homogenous mixtures of different base refrigerants (R134a, R152a, R290) and nanoparticles (TiO2 and Al2O3) with 0-5 wt.% nanoparticle concentration. The effects of variation in system operational parameters (nanoparticle mass fraction, evaporator pressure, condenser pressure and superheating degree of motive flow) on energy efficiency and exergy efficiency of the combined cycle are reported. Additionally, net power production, refrigeration capacity, heat input to the combined cycle and their exergy contents are given for the case of TiO2/R290 nanorefrigerant use in ERC. This study is the first ERC analysis in which the effect of R152a and R290 base refrigerants and TiO2 nanoparticle use on ERC performance is investigated. The results show that as the nanoparticle concentration and evaporator pressure increase, the energy and exergy efficiencies also increase. On the other hand, with an increase in condenser pressure and the superheating degree of the motive flow, a decrease in energy and exergy efficiencies is observed. Under all the considered operational conditions of the combined cycle, the highest efficiency results are obtained for R290 and the lowest for R134a base refrigerants.
{"title":"Investigation on the effects of nanorefrigerants in a combined cycle of ejector refrigeration cycle and Kalina cycle","authors":"Candeniz Seçkin","doi":"10.1115/1.4063920","DOIUrl":"https://doi.org/10.1115/1.4063920","url":null,"abstract":"The main objective of this study is to carry out the thermodynamic analysis of a new power/ refrigeration combined cycle which consists of an ejector refrigeration cycle (ERC) and a Kalina cycle. In ERC, nanorefrigerants are used as the working fluid. Used nanorefrigerants are homogenous mixtures of different base refrigerants (R134a, R152a, R290) and nanoparticles (TiO2 and Al2O3) with 0-5 wt.% nanoparticle concentration. The effects of variation in system operational parameters (nanoparticle mass fraction, evaporator pressure, condenser pressure and superheating degree of motive flow) on energy efficiency and exergy efficiency of the combined cycle are reported. Additionally, net power production, refrigeration capacity, heat input to the combined cycle and their exergy contents are given for the case of TiO2/R290 nanorefrigerant use in ERC. This study is the first ERC analysis in which the effect of R152a and R290 base refrigerants and TiO2 nanoparticle use on ERC performance is investigated. The results show that as the nanoparticle concentration and evaporator pressure increase, the energy and exergy efficiencies also increase. On the other hand, with an increase in condenser pressure and the superheating degree of the motive flow, a decrease in energy and exergy efficiencies is observed. Under all the considered operational conditions of the combined cycle, the highest efficiency results are obtained for R290 and the lowest for R134a base refrigerants.","PeriodicalId":15676,"journal":{"name":"Journal of Energy Resources Technology-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136317226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Two-stroke spark-ignition engines play a significant role in the field of power sources of small and medium unmanned aerial vehicles. There is a certain transition from burning gasoline to aviation kerosene(or heavy oil) and from carburetor or inlet injection system to direct-injection fuel system. However, the performance of two-stroke spark-ignition direct-injection engines fueled with aviation kerosene was not very ideal under heavy loads. Generally, the mixture formation is very key for engine combustion and performance, while injection parameters have great effects on mixture formation. Thus, various injection parameters of a two-stroke direct-injection kerosene engine were examined here. The results showed too early or too late injection timing(tinj) would deteriorate the mixture formation, resulting in lower brake power and brake thermal efficiency. Here the most suitable tinj was 150°CA BTDC. Too high or too low injection pressure(pinj) caused fuel short-circuit loss and poor mixture quality, so the optimum pinj was 10MPa. Too large injector installation angle(β) easily results in fuel spray impingement, and too small β causes fuel short circuit loss. Therefore, the best β was concluded to be 30° in this paper.
{"title":"Impacts of Injection Parameters on the Mixture Formation and Performance of Two-Stroke Spark-Ignition Direct-Injection Aviation Kerosene Engine","authors":"Ying Wang, Qiongyang Zhou","doi":"10.1115/1.4063925","DOIUrl":"https://doi.org/10.1115/1.4063925","url":null,"abstract":"Abstract Two-stroke spark-ignition engines play a significant role in the field of power sources of small and medium unmanned aerial vehicles. There is a certain transition from burning gasoline to aviation kerosene(or heavy oil) and from carburetor or inlet injection system to direct-injection fuel system. However, the performance of two-stroke spark-ignition direct-injection engines fueled with aviation kerosene was not very ideal under heavy loads. Generally, the mixture formation is very key for engine combustion and performance, while injection parameters have great effects on mixture formation. Thus, various injection parameters of a two-stroke direct-injection kerosene engine were examined here. The results showed too early or too late injection timing(tinj) would deteriorate the mixture formation, resulting in lower brake power and brake thermal efficiency. Here the most suitable tinj was 150°CA BTDC. Too high or too low injection pressure(pinj) caused fuel short-circuit loss and poor mixture quality, so the optimum pinj was 10MPa. Too large injector installation angle(β) easily results in fuel spray impingement, and too small β causes fuel short circuit loss. Therefore, the best β was concluded to be 30° in this paper.","PeriodicalId":15676,"journal":{"name":"Journal of Energy Resources Technology-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136317748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xinhao Ye, Jinhu Li, Wei Lu, Xuan Liu, Zhiwei Wang, Chisen Liang
Abstract In this study, the same moles of alkali and alkaline earth metallic species were introduced into pine wood to investigate their effects on biomass pyrolysis and carbon dioxide-assisted gasification. First, thermogravimetric analysis was conducted to examine the pyrolytic behavior of pine wood loaded with alkali and alkaline earth metallic species. A semi-batch fixed bed platform was used to quantify gaseous product parameters, including gas mass flow rate, gas yield, recovered energy, energy efficiency, and net carbon dioxide consumption. Thermogravimetric results indicated that the loading of alkali and alkaline earth metallic species promoted the thermal decomposition of pine wood at low temperatures, but an inhibitory effect was observed at high temperatures. In terms of pyrolysis, adding alkaline earth metals increased syngas yields, and recovered energy, as well as energy efficiency, whereas alkali metals had the opposite effect. For the gasification, the loading of alkali metals showed a stronger catalytic than the pine wood loaded with alkaline earth metals. Based on the evolution of carbon monoxide, the effects of alkali and alkaline earth metallic species on enhancing the biochar's gasification reactivity were in the sequence of sodium > potassium > calcium > magnesium. In addition, the addition of alkali metals exhibited a stronger capacity for carbon dioxide consumption, which contributed to the management of the greenhouse gas. Considering only energy efficiency, adding alkaline earth metals in biomass pyrolysis is an optimal choice due to the higher overall energy efficiency obtained in less time.
{"title":"Effect of Alkali and Alkaline Earth Metallic Species on Gas Evolution and Energy Efficiency Evolution in Pyrolysis and Co2-Assisted Gasification","authors":"Xinhao Ye, Jinhu Li, Wei Lu, Xuan Liu, Zhiwei Wang, Chisen Liang","doi":"10.1115/1.4063849","DOIUrl":"https://doi.org/10.1115/1.4063849","url":null,"abstract":"Abstract In this study, the same moles of alkali and alkaline earth metallic species were introduced into pine wood to investigate their effects on biomass pyrolysis and carbon dioxide-assisted gasification. First, thermogravimetric analysis was conducted to examine the pyrolytic behavior of pine wood loaded with alkali and alkaline earth metallic species. A semi-batch fixed bed platform was used to quantify gaseous product parameters, including gas mass flow rate, gas yield, recovered energy, energy efficiency, and net carbon dioxide consumption. Thermogravimetric results indicated that the loading of alkali and alkaline earth metallic species promoted the thermal decomposition of pine wood at low temperatures, but an inhibitory effect was observed at high temperatures. In terms of pyrolysis, adding alkaline earth metals increased syngas yields, and recovered energy, as well as energy efficiency, whereas alkali metals had the opposite effect. For the gasification, the loading of alkali metals showed a stronger catalytic than the pine wood loaded with alkaline earth metals. Based on the evolution of carbon monoxide, the effects of alkali and alkaline earth metallic species on enhancing the biochar's gasification reactivity were in the sequence of sodium > potassium > calcium > magnesium. In addition, the addition of alkali metals exhibited a stronger capacity for carbon dioxide consumption, which contributed to the management of the greenhouse gas. Considering only energy efficiency, adding alkaline earth metals in biomass pyrolysis is an optimal choice due to the higher overall energy efficiency obtained in less time.","PeriodicalId":15676,"journal":{"name":"Journal of Energy Resources Technology-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135570127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Haocheng Ji, Lingfeng Zhong, Songhong Li, Yufeng Chen, Rui Liu
The aviation kerosene piston engine (AKPE) is the main power system for small- and medium-sized unmanned aerial vehicles (UAVs). Conventional AKPEs use carburetors or port fuel injection (PFI) as fuel supply, resulting in poor cold start performance and difficulty in forming an economically efficient stratified mixture. In addition, two-stroke AKPEs using carburetors or PFI have serious scavenging losses. These reasons lead to the poor economic performance of conventional AKPEs. Direct injection (DI) can be controlled through precise injection timing to form a stratified mixture. The combustion of stratified mixtures in engines can effectively improve the fuel economy and endurance flight time characteristics of UAVs. As a special DI injector, self-pressurized injectors have great potential in the power field of UAVs. To effectively apply self-pressurized injectors on UAV engines and improve the economy, an engine model and a self-pressurized injector spray model are established and verified in this paper. The single injection strategy and segmented injection strategy for forming stratified mixtures are explored, and the combustion performance is studied. The main conclusions are as follows: the optimal installation angle of the injector is 15°, which yields excellent results in the formation of the mixture at this angle. When the fuel injection quantity is small, utilizing a single injection strategy combined with delaying the end of the injection phase (EOIP) can form a stratified mixture. Reducing the angle difference between the EOIP and the ignition timing can improve the power and economy. As the fuel injection quantity is large, a stratified mixture can be formed through two-stage injection. When the fuel injection ratio is 4:1, the uniformity of the mixture distribution in the combustion chamber is significantly improved. Adjusting the 2nd EOIP between a 35° crank angle (CA) before top dead centre (BTDC) and a 30° CA BTDC can achieve a stratified mixture with good economy and power performance.
{"title":"Effects of a Self-Pressurized Injection Strategy on the Formation of a Stratified Mixture and the Combustion of an Aviation Kerosene Piston Engine","authors":"Haocheng Ji, Lingfeng Zhong, Songhong Li, Yufeng Chen, Rui Liu","doi":"10.1115/1.4063842","DOIUrl":"https://doi.org/10.1115/1.4063842","url":null,"abstract":"The aviation kerosene piston engine (AKPE) is the main power system for small- and medium-sized unmanned aerial vehicles (UAVs). Conventional AKPEs use carburetors or port fuel injection (PFI) as fuel supply, resulting in poor cold start performance and difficulty in forming an economically efficient stratified mixture. In addition, two-stroke AKPEs using carburetors or PFI have serious scavenging losses. These reasons lead to the poor economic performance of conventional AKPEs. Direct injection (DI) can be controlled through precise injection timing to form a stratified mixture. The combustion of stratified mixtures in engines can effectively improve the fuel economy and endurance flight time characteristics of UAVs. As a special DI injector, self-pressurized injectors have great potential in the power field of UAVs. To effectively apply self-pressurized injectors on UAV engines and improve the economy, an engine model and a self-pressurized injector spray model are established and verified in this paper. The single injection strategy and segmented injection strategy for forming stratified mixtures are explored, and the combustion performance is studied. The main conclusions are as follows: the optimal installation angle of the injector is 15°, which yields excellent results in the formation of the mixture at this angle. When the fuel injection quantity is small, utilizing a single injection strategy combined with delaying the end of the injection phase (EOIP) can form a stratified mixture. Reducing the angle difference between the EOIP and the ignition timing can improve the power and economy. As the fuel injection quantity is large, a stratified mixture can be formed through two-stage injection. When the fuel injection ratio is 4:1, the uniformity of the mixture distribution in the combustion chamber is significantly improved. Adjusting the 2nd EOIP between a 35° crank angle (CA) before top dead centre (BTDC) and a 30° CA BTDC can achieve a stratified mixture with good economy and power performance.","PeriodicalId":15676,"journal":{"name":"Journal of Energy Resources Technology-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135823239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bin Xu, Ke Hu, Jianxing Liao, Hong Wang, Yuhang Teng, Jiashun Luo, Cheng Cao
Abstract The utilization of low-enthalpy geothermal systems holds substantial potential for mitigating the greenhouse effect. However, the thermal efficiency of geothermal systems is significantly influenced by the spatial distribution of reservoir property, particularly permeability and porosity. In this work, we systematically investigate the impact of anisotropic heterogeneity in porosity and permeability on geothermal performance using numerical method. The thermal performance is evaluated based on parameters such as thermal production lifetime, thermal breakthrough time, and thermal production energy. Our findings indicate that with an increase in correlation length from 100 to 500m, highly heterogeneous reservoirs tend to regionalize pores, forming highly conductive fluid flow channels. This led to shorter thermal production lifetime and thermal breakthrough time. Moreover, the thermal performance varied significantly with different rotation angles in a double well layout, displaying a maximum difference of 41.17% compared to homogeneous reservoir. This difference decreased with the number of wells, reaching 32.82% and 16.66% in triple and quadruple well layouts, respectively. Consequently, the thermal performance was more stable under uncertain well positions in the quadruple well layout, but with reduced heat extraction efficiency. Our research results provide valuable insights into the impact of anisotropic heterogeneity on thermal performance in low-enthalpy geothermal systems.
{"title":"Numerical Investigation on Thermal Performance in Low-enthalpy Geothermal System under the Impact of Anisotropic Reservoir Heterogeneity and Well Layout","authors":"Bin Xu, Ke Hu, Jianxing Liao, Hong Wang, Yuhang Teng, Jiashun Luo, Cheng Cao","doi":"10.1115/1.4063839","DOIUrl":"https://doi.org/10.1115/1.4063839","url":null,"abstract":"Abstract The utilization of low-enthalpy geothermal systems holds substantial potential for mitigating the greenhouse effect. However, the thermal efficiency of geothermal systems is significantly influenced by the spatial distribution of reservoir property, particularly permeability and porosity. In this work, we systematically investigate the impact of anisotropic heterogeneity in porosity and permeability on geothermal performance using numerical method. The thermal performance is evaluated based on parameters such as thermal production lifetime, thermal breakthrough time, and thermal production energy. Our findings indicate that with an increase in correlation length from 100 to 500m, highly heterogeneous reservoirs tend to regionalize pores, forming highly conductive fluid flow channels. This led to shorter thermal production lifetime and thermal breakthrough time. Moreover, the thermal performance varied significantly with different rotation angles in a double well layout, displaying a maximum difference of 41.17% compared to homogeneous reservoir. This difference decreased with the number of wells, reaching 32.82% and 16.66% in triple and quadruple well layouts, respectively. Consequently, the thermal performance was more stable under uncertain well positions in the quadruple well layout, but with reduced heat extraction efficiency. Our research results provide valuable insights into the impact of anisotropic heterogeneity on thermal performance in low-enthalpy geothermal systems.","PeriodicalId":15676,"journal":{"name":"Journal of Energy Resources Technology-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135824097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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