Study On Combined Performance Of Two - Phase Flow Type Separating Heat Pipe And Its Engineering Application

Compared to conventional heat exchangers and regular heat pipes, two phase flow pump-assisted heat pipe has advantages, for example, the installation isn’t bound to the height difference of the heat transfer situation or the heat transfer distance, and it’s easy for further maintenance, which makes this kind of heat pipe have a broad engineering application prospect.Through experiment and Fluent simulation studies on combination effect of the two phase flow pump-assisted heat pipe, this paper presents the maximum and optimized performance of the combination effect.Firstly, this paper presents the introduction of the working principle of heat pipe, the present oscillating heat pipe, the rotating heat pipe and the two phase flow pump-assisted heat pipe,as well as the introduction of the core element of the heat transfer of the heat pipe--working fluid.By building the experimental apparatus of the two phase flow pump-assisted heat pipe units, the combination effect for energy saving in cooling and dehumidifying application is analyzed. The results show that:there is a optimum units for pump-assisted heat pipe application. In the engineering application of cooling and dehumidifying process, 3 sets of pump-assisted heat pipe is recommended when the required supply air temperature is about 20℃; 4 sets of pump-assisted heat pipe when the required supply air temperature is 24℃. Thus the control of the supply air temperature is by changing 1 or 2 sets of the heat pipes.By adding a refrigeration unit to the experimental apparatus of heat pipe, the dew point temperature could reach below 0 ℃. The result shows that the dehumidifying apparatus working under 0 ℃ is doable, however, a proper defrosting design is needed.The energy saving rate is 21.6% when 1 set of heat pipe is working,increasing by 5.7% when another unit is switched to work. By the numerical simulation of the two phase characteristics of the horizontal straight pipe using Fluent, the flow can be observed directly. By the analysis of heat transfer performance of pump-assisted heat pipe in the same boundary conditions and the same temperature difference of heat transfer, the results show that the heat transfer performance of the inside and outside heat pipe are nearly equal and stable.Under the simulation of the horizontal and vertical flow in the same boundary conditions, the results show that the horizontal pipe has huge advantage over the vertical pipe in pump-assisted heat pipe.In the end of this paper, by the earlier experimental and Fluent simulation studies on the pump-assisted heat pipe, a device using pump-assisted heat pipe units for heat recovery of flue gas is designed. Under this design scheme of pump-assisted heat pipe units, the recovered heat of1337.37 KW could be used to preheat the air, and the cost of the investment can be got back after about 1 year, The two phase flow pump-assisted heat pipe has a broad application prospect. The efficient recovery of energy can come true,as well as the replacement of the present heat transfer devices for equipment upgrading.It deserves widespread applications.