An exhaust heat recovery generator is proposed to be integrated with conventional gas-fired triple-effect LiBr/water absorption cooling cycles to improve system energy efficiency. As a case study, simulation of the no...An exhaust heat recovery generator is proposed to be integrated with conventional gas-fired triple-effect LiBr/water absorption cooling cycles to improve system energy efficiency. As a case study, simulation of the novel cycle based on promising parallel flow with cooling capacity of 1 150 kW is carried out under various heat recovery generator vapor production ratios ranging from 0 to 3.5%. The life cycle saving economic analysis, for which the annual gas conservation is estimated with Bin method, is employed to prove the worthiness of extra expenditure. Results show that the optimum gas saving revenue is obtained at 2.8% heat recovery generator vapor production ratio with 42 kW exhaust heat recovered, and the system energy efficiency is improved from 1.78 to 1.83. The initial investment of exchanger can be paid back within 7 years and 9 000 CNY of gas saving revenue will be achieved over the 15-year life cycle of the machine. This technology can be easily implemented and present desirable economic effects, which is feasible to the development of triple-effect absorption cycles.展开更多
Innovatively addressing the challenge of difficult winter starts for vehicles in northern regions,this study has developed a Thermally Controlled Preheating Engine Activation System.This system ingeniously integrates ...Innovatively addressing the challenge of difficult winter starts for vehicles in northern regions,this study has developed a Thermally Controlled Preheating Engine Activation System.This system ingeniously integrates a thermal insulation kettle,an efficient water pump,precision valves,and temperature sensors,all closely linked with the engine’s coolant circulation system.In cold environments,the system automatically initiates a preheating mechanism by circulating and heating the coolant,significantly enhancing engine startup efficiency and reducing wear caused by cold starts.The anticipated outcome of this research is to substantially improve the operational reliability of vehicles in cold climates,extend their lifespan,promote energy conservation and emissions reduction,and drive the automotive industry towards greener,more efficient,and intelligent technologies,thus laying a solid foundation for industry upgrades and transformation.展开更多
Geological hazards caused by high-temperature rocks cooling down after encountering water are closely related to underground mining and tunneling projects.To fully understand the impact of temperature changes on the m...Geological hazards caused by high-temperature rocks cooling down after encountering water are closely related to underground mining and tunneling projects.To fully understand the impact of temperature changes on the mechanical properties of rocks,yellow rust granite samples were subjected to heating-natural cooling and heating-water cooling cycles to experimentally study the effects of these processes on the mechanical properties of the samples.The mechanism of the heating-cooling process on the macromechanical properties of the rock was discussed.Based on the Drucker-Prager criterion and Weibull distribution function,a damage variable correction factor was introduced to reflect the post-peak strain softening characteristics,and a thermo-mechanical coupled damage constitutive model of the granite was established.The results showed that in the natural cooling mode,the mechanical properties deteriorate significantly when the temperature exceeded 600C,and the failure mode changed from brittle failure to ductile failure.In the water cooling mode,the peak strength and deformation modulus increased at temperatures below 400C with an increase in the cycle number,while at 600C,the peak strength and elastic modulus notably decreased.The peak strain increased with the increase of the cycle number and temperature at all temperatures,and the failure mode of the granite tended to change from tensile failure mode to shear failure mode.The experimental results were used to validate the damage constitutive model.The shape parameter r and scale parameter S in the Weibull distribution function of the model were used as indicators to reflect the brittleness degree and peak strength.This study helps to understand the behavior of rocks in hightemperature environments,in order to prevent and mitigate potential geological hazards.展开更多
基金Supported by National Natural Science Foundation of China (No. 50376044)
文摘An exhaust heat recovery generator is proposed to be integrated with conventional gas-fired triple-effect LiBr/water absorption cooling cycles to improve system energy efficiency. As a case study, simulation of the novel cycle based on promising parallel flow with cooling capacity of 1 150 kW is carried out under various heat recovery generator vapor production ratios ranging from 0 to 3.5%. The life cycle saving economic analysis, for which the annual gas conservation is estimated with Bin method, is employed to prove the worthiness of extra expenditure. Results show that the optimum gas saving revenue is obtained at 2.8% heat recovery generator vapor production ratio with 42 kW exhaust heat recovered, and the system energy efficiency is improved from 1.78 to 1.83. The initial investment of exchanger can be paid back within 7 years and 9 000 CNY of gas saving revenue will be achieved over the 15-year life cycle of the machine. This technology can be easily implemented and present desirable economic effects, which is feasible to the development of triple-effect absorption cycles.
文摘Innovatively addressing the challenge of difficult winter starts for vehicles in northern regions,this study has developed a Thermally Controlled Preheating Engine Activation System.This system ingeniously integrates a thermal insulation kettle,an efficient water pump,precision valves,and temperature sensors,all closely linked with the engine’s coolant circulation system.In cold environments,the system automatically initiates a preheating mechanism by circulating and heating the coolant,significantly enhancing engine startup efficiency and reducing wear caused by cold starts.The anticipated outcome of this research is to substantially improve the operational reliability of vehicles in cold climates,extend their lifespan,promote energy conservation and emissions reduction,and drive the automotive industry towards greener,more efficient,and intelligent technologies,thus laying a solid foundation for industry upgrades and transformation.
基金funded by the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX22_0613)National Natural Science Foundation of China(Grant Nos.41831278,51878249).
文摘Geological hazards caused by high-temperature rocks cooling down after encountering water are closely related to underground mining and tunneling projects.To fully understand the impact of temperature changes on the mechanical properties of rocks,yellow rust granite samples were subjected to heating-natural cooling and heating-water cooling cycles to experimentally study the effects of these processes on the mechanical properties of the samples.The mechanism of the heating-cooling process on the macromechanical properties of the rock was discussed.Based on the Drucker-Prager criterion and Weibull distribution function,a damage variable correction factor was introduced to reflect the post-peak strain softening characteristics,and a thermo-mechanical coupled damage constitutive model of the granite was established.The results showed that in the natural cooling mode,the mechanical properties deteriorate significantly when the temperature exceeded 600C,and the failure mode changed from brittle failure to ductile failure.In the water cooling mode,the peak strength and deformation modulus increased at temperatures below 400C with an increase in the cycle number,while at 600C,the peak strength and elastic modulus notably decreased.The peak strain increased with the increase of the cycle number and temperature at all temperatures,and the failure mode of the granite tended to change from tensile failure mode to shear failure mode.The experimental results were used to validate the damage constitutive model.The shape parameter r and scale parameter S in the Weibull distribution function of the model were used as indicators to reflect the brittleness degree and peak strength.This study helps to understand the behavior of rocks in hightemperature environments,in order to prevent and mitigate potential geological hazards.