The temperature separation was discovered inside the short vortex chamber （H/D = 0.18）. Experiments revealed that the highest temperature of the periphery was 465 ℃, and the lowest temperature of the central zone w...The temperature separation was discovered inside the short vortex chamber （H/D = 0.18）. Experiments revealed that the highest temperature of the periphery was 465 ℃, and the lowest temperature of the central zone was -45 ℃ （the compressed air was pumped into the chamber at room temperature）. The objective of this paper is to proof that this temperature separation effect cannot be explained by conventional heat transfer processes. To explain this phenomenon, the concept of PGEW （Pressure Gradient Elastic Waves） is proposed. PGEW are kind of elastic waves, which operate in compressible fluids with pressure gradients and density fluctuations. The result of PGEW propagation is a heat transfer from area of low pressure to high pressure zone. The physical model of a gas in a strong field of mass forces is proposed to substantiate the PGEW existence. This physical model is intended for the construction of a theory of PGEW. Understanding the processes associated with the PGEW permits the possibility of creating new devices for energy saving and low potential heat utilization, which have unique properties.展开更多
The thermal performance of a“U”type earth-to-air heat exchanger is presented in this experimental study.The device has a serial-connected vertical configuration.The wells where tubes were installed have a depth of f...The thermal performance of a“U”type earth-to-air heat exchanger is presented in this experimental study.The device has a serial-connected vertical configuration.The wells where tubes were installed have a depth of fewer than 3 m and are separated every 1.5 m,using an installation area of 3m2.The experimentation was carried out in March in Morelos,Mexico when the environmental temperature reaches 35℃ during the day.The performance of the device was measured and compared to the requirements of an office for cooling purposes within a university campus to reproduce the space restrictions found in urbanized areas.By using a small land surface,it is feasible for urbanized areas.The air temperature inside the“U”type earth-to-air heat exchanger,the surrounding soil temperature,the airspeed,and the power consumed by the fan were measured.The air temperature and the fan’s power consumption data were obtained by modifying the airspeed in four constant values,from 1.3 m/s to 6.6 m/s.Results show that the device evaluated in this work has adequate thermal performance for cooling purposes compared to the requirements of an office.A decrease in air temperature was recorded in a range of 5.1℃ to 9.4℃.Over 70%of the total temperature difference was reached in the first well,where the average soil thermal disturbance at 5 cm was 2.8℃.The device achieved a maximum COP of 12.8 and a maximum effectiveness of 88.4%.With these results,it is concluded that the system is suitable for cooling purposes in areas with space restrictions.This work is novel since the dimensions available for installation in urbanized areas are considered and compared with the thermal requirements of an office.In addition to the fact that there are no published works with vertical heat exchangers connected in series.展开更多
In the current study, simulations based on the engineering equation solver （EES） software are performed to determine the suitable working fluid for the simple organic Rankine cYcle system in different temperature ra...In the current study, simulations based on the engineering equation solver （EES） software are performed to determine the suitable working fluid for the simple organic Rankine cYcle system in different temperature ranges. Under the condition of various temperatures and a constant thermal power of the flue gas, the influence of different organic working fluids on the efficiency of the subcritical organic Rankine cycle power generation system is studied, and its efficiency and other parameters are compared with those of the regenerator system. It is shown that the efficiency of the subcritical organic Rankine cycle system is the best when the parameters of the working fluid in the expander inlet are in the saturation state. And for the organic Rankine cycle, the R245fa is better than other working fluids and the efficiency of the system reaches up to 10.2% when the flammability, the toxicity, the ozone depletion, the greenhouse effect and other factors of the working fluids are considered. The R60 l a working fluid can be used for the high-temperature heat source, however, because of its high flammability, new working fluid should be investigated. Under the same condition, the efficiency of the organic Rankine cycle power generation system with an internal heat exchanger is higher than that of the simple system without the internal heat exchanger, but the efficiency is related to the properties of the working fluid and the temperature of the heat source.展开更多
利用Aspen Plus对某炼油厂4.20 Mt/a催化裂化(FCC)装置进行建模预测。基于所建模型提取装置冷热物流数据,利用夹点技术对整个装置进行换热网络分析,发现原FCC装置吸收稳定系统存在能耗高、热公用工程消耗大,原料油混合温差大,轻柴油、...利用Aspen Plus对某炼油厂4.20 Mt/a催化裂化(FCC)装置进行建模预测。基于所建模型提取装置冷热物流数据,利用夹点技术对整个装置进行换热网络分析,发现原FCC装置吸收稳定系统存在能耗高、热公用工程消耗大,原料油混合温差大,轻柴油、重柴油及产品油浆高质低用,除盐水终温较低,除氧器蒸汽消耗量大等问题。通过优化稳定塔回流比、补充吸收剂流量等方法降低吸收稳定系统负荷,优化分馏塔中段取热比例多产高品位蒸汽,并利用夹点技术优化装置换热网络。结果表明:优化后,可节省蒸汽量27.3 t h,相当于节能16603 tOE a(1 tOE=41.8 GJ)或23757 tCE a(1 tCE=29.27 GJ),减少二氧化碳排放量76457 t a,节能效果优异;同时,改造还减少FCC装置外送热媒水量300 t h,装置内利用热媒水10.27 MW的余热,减少了热量损失。展开更多
文摘The temperature separation was discovered inside the short vortex chamber （H/D = 0.18）. Experiments revealed that the highest temperature of the periphery was 465 ℃, and the lowest temperature of the central zone was -45 ℃ （the compressed air was pumped into the chamber at room temperature）. The objective of this paper is to proof that this temperature separation effect cannot be explained by conventional heat transfer processes. To explain this phenomenon, the concept of PGEW （Pressure Gradient Elastic Waves） is proposed. PGEW are kind of elastic waves, which operate in compressible fluids with pressure gradients and density fluctuations. The result of PGEW propagation is a heat transfer from area of low pressure to high pressure zone. The physical model of a gas in a strong field of mass forces is proposed to substantiate the PGEW existence. This physical model is intended for the construction of a theory of PGEW. Understanding the processes associated with the PGEW permits the possibility of creating new devices for energy saving and low potential heat utilization, which have unique properties.
文摘The thermal performance of a“U”type earth-to-air heat exchanger is presented in this experimental study.The device has a serial-connected vertical configuration.The wells where tubes were installed have a depth of fewer than 3 m and are separated every 1.5 m,using an installation area of 3m2.The experimentation was carried out in March in Morelos,Mexico when the environmental temperature reaches 35℃ during the day.The performance of the device was measured and compared to the requirements of an office for cooling purposes within a university campus to reproduce the space restrictions found in urbanized areas.By using a small land surface,it is feasible for urbanized areas.The air temperature inside the“U”type earth-to-air heat exchanger,the surrounding soil temperature,the airspeed,and the power consumed by the fan were measured.The air temperature and the fan’s power consumption data were obtained by modifying the airspeed in four constant values,from 1.3 m/s to 6.6 m/s.Results show that the device evaluated in this work has adequate thermal performance for cooling purposes compared to the requirements of an office.A decrease in air temperature was recorded in a range of 5.1℃ to 9.4℃.Over 70%of the total temperature difference was reached in the first well,where the average soil thermal disturbance at 5 cm was 2.8℃.The device achieved a maximum COP of 12.8 and a maximum effectiveness of 88.4%.With these results,it is concluded that the system is suitable for cooling purposes in areas with space restrictions.This work is novel since the dimensions available for installation in urbanized areas are considered and compared with the thermal requirements of an office.In addition to the fact that there are no published works with vertical heat exchangers connected in series.
文摘In the current study, simulations based on the engineering equation solver （EES） software are performed to determine the suitable working fluid for the simple organic Rankine cYcle system in different temperature ranges. Under the condition of various temperatures and a constant thermal power of the flue gas, the influence of different organic working fluids on the efficiency of the subcritical organic Rankine cycle power generation system is studied, and its efficiency and other parameters are compared with those of the regenerator system. It is shown that the efficiency of the subcritical organic Rankine cycle system is the best when the parameters of the working fluid in the expander inlet are in the saturation state. And for the organic Rankine cycle, the R245fa is better than other working fluids and the efficiency of the system reaches up to 10.2% when the flammability, the toxicity, the ozone depletion, the greenhouse effect and other factors of the working fluids are considered. The R60 l a working fluid can be used for the high-temperature heat source, however, because of its high flammability, new working fluid should be investigated. Under the same condition, the efficiency of the organic Rankine cycle power generation system with an internal heat exchanger is higher than that of the simple system without the internal heat exchanger, but the efficiency is related to the properties of the working fluid and the temperature of the heat source.
文摘利用Aspen Plus对某炼油厂4.20 Mt/a催化裂化(FCC)装置进行建模预测。基于所建模型提取装置冷热物流数据,利用夹点技术对整个装置进行换热网络分析,发现原FCC装置吸收稳定系统存在能耗高、热公用工程消耗大,原料油混合温差大,轻柴油、重柴油及产品油浆高质低用,除盐水终温较低,除氧器蒸汽消耗量大等问题。通过优化稳定塔回流比、补充吸收剂流量等方法降低吸收稳定系统负荷,优化分馏塔中段取热比例多产高品位蒸汽,并利用夹点技术优化装置换热网络。结果表明:优化后,可节省蒸汽量27.3 t h,相当于节能16603 tOE a(1 tOE=41.8 GJ)或23757 tCE a(1 tCE=29.27 GJ),减少二氧化碳排放量76457 t a,节能效果优异;同时,改造还减少FCC装置外送热媒水量300 t h,装置内利用热媒水10.27 MW的余热,减少了热量损失。
