For efficient utilization of a limited geothermal resource in practical projects,the cycle parameters were comprehensively analyzed by combining with the heat transfer performance of the plate heat exchanger,with a va...For efficient utilization of a limited geothermal resource in practical projects,the cycle parameters were comprehensively analyzed by combining with the heat transfer performance of the plate heat exchanger,with a variation of flowrate of R245 fa.The influence of working fluid flowrate on a 500 W ORC system was investigated.Adjusting the working fluid flowrate to an optimal value results in the most efficient heat transfer and hence the optimal heat transfer parameters of the plate heat exchanger can be determined.Therefore,for the ORC systems,optimal working fluid flowrate should be controlled.Using different temperature hot water as the heat source,it is found that the optimal flowrate increases by 6-10 L/h with 5 ℃ increment of hot water inlet temperature.During experiment,lower degree of superheat of the working fluid at the outlet the plate heat exchanger may lead to unstable power generation.It is considered that the plate heat exchanger has a compact construction which makes its bulk so small that liquid mixture causes the unstable power generation.To avoid this phenomenon,the flow area of plate heat exchanger should be larger than the designed one.Alternatively,installing a small shell and tube heat exchanger between the outlet of plate heat exchanger and the inlet of expander can be another solution.展开更多
The main objective of the present experimental study is to analyze the turbulent structure in humid airnon-premixed flame, and determine the effect of humidity on the flow field and the flame stability limit in turbul...The main objective of the present experimental study is to analyze the turbulent structure in humid airnon-premixed flame, and determine the effect of humidity on the flow field and the flame stability limit in turbulentnon-premixed flame. Particle Image Velocimetry (PIV) is used to capture the instantaneous appearance ofvortex structures and obtain the quantitative velocity field. The distributions of Reynolds shear stress, mean androot-mean squared fluctuating (rms) velocities are examined to get insight into the effect of fuel-to-air velocity ratioon velocity flow field. The results show that with steam addition, the air-driven vortex in the bluff-body wakeis thinner; the biggest peaks of rms velocity and Reynolds shear stress are lower; the distance between the peaksof rms velocity on the sides of centerline reduces. Besides these, the flame stability is affected. Both central fuelpenetration limit and partially quenching limit reduce with steam addition.展开更多
基金Project (2012AA053001) supported by High-tech Research and Development Program of China
文摘For efficient utilization of a limited geothermal resource in practical projects,the cycle parameters were comprehensively analyzed by combining with the heat transfer performance of the plate heat exchanger,with a variation of flowrate of R245 fa.The influence of working fluid flowrate on a 500 W ORC system was investigated.Adjusting the working fluid flowrate to an optimal value results in the most efficient heat transfer and hence the optimal heat transfer parameters of the plate heat exchanger can be determined.Therefore,for the ORC systems,optimal working fluid flowrate should be controlled.Using different temperature hot water as the heat source,it is found that the optimal flowrate increases by 6-10 L/h with 5 ℃ increment of hot water inlet temperature.During experiment,lower degree of superheat of the working fluid at the outlet the plate heat exchanger may lead to unstable power generation.It is considered that the plate heat exchanger has a compact construction which makes its bulk so small that liquid mixture causes the unstable power generation.To avoid this phenomenon,the flow area of plate heat exchanger should be larger than the designed one.Alternatively,installing a small shell and tube heat exchanger between the outlet of plate heat exchanger and the inlet of expander can be another solution.
基金supported by a Grant-in-Aid for Scientific Research through research grant number 2007CB210102 from State Key Fundamental Researeh Program of China.
文摘The main objective of the present experimental study is to analyze the turbulent structure in humid airnon-premixed flame, and determine the effect of humidity on the flow field and the flame stability limit in turbulentnon-premixed flame. Particle Image Velocimetry (PIV) is used to capture the instantaneous appearance ofvortex structures and obtain the quantitative velocity field. The distributions of Reynolds shear stress, mean androot-mean squared fluctuating (rms) velocities are examined to get insight into the effect of fuel-to-air velocity ratioon velocity flow field. The results show that with steam addition, the air-driven vortex in the bluff-body wakeis thinner; the biggest peaks of rms velocity and Reynolds shear stress are lower; the distance between the peaksof rms velocity on the sides of centerline reduces. Besides these, the flame stability is affected. Both central fuelpenetration limit and partially quenching limit reduce with steam addition.
