Study On Coupling Heat Transfer Characteristics In Plate Heat Exchanger Filled With Porous Medium Under Local Thermal Non-Equilibrium Condition

The energy problem is the most important problem in the world today.The rational utilization of the existing energy and the development of new energy are the worldwide research topics.The heat exchanger is the key equipment to rationally utilize and save the existing energy and develop new energy.Its reasonable design and performance improvement are directly related to the rational utilization of the existing energy.In this dissertation,through combining analytical and numerical methods for the filling flow in porous media of plate heat exchanger and in thermal dissipation are studied.Flat contact with the outside wall of the heat exchanger for adiabatic conditions,considering internal wall thickness of the plate heat exchanger heat exchange,and assumes that the channel fluid flow and heat transfer in the full development period.Respectively using Darcy-Brinkman model and local heat balance model(LTNE)to establish a plate heat exchanger in the internal control of fluid flow and heat transfer equation.Using the theoretical method and numerical simulation method for filled with porous medium heat exchanger were studied,and analyzed the results of two methods.Using theoretical method,ignore the axial heat conduction channel walls,was used to solve control equations and the settlement results validate: downstream with the results of numerical simulation is verified,countercurrent with theoretical calculation results and the numerical simulation results are verified,the result is very consistent,prove the validity of the method.Downstream and upstream is analyzed emphatically under the condition of the heat capacity ratio,coefficient of thermal conductivity and porosity,Da,and Bi effect the performance of the temperature field and heat transfer.Results show that the side channel and the heat transfer performance depends not only on the side of the channel parameters,also influenced by other side channel parameter;Under different flow conditions,the above parameters on the influence of the heat transfer performance of plate heat exchanger is not exactly the same.Then use numerical simulation methods to filled with porous medium plate heat exchanger is analyzed,mainly on the frictional heat flux and local Ni are analyzed.The results show that when the heat capacity ratio not to 1,due to the axial heat conduction,theory method and the result of numerical simulation method is different.As a result of the existence of axial heat conduction,heat flow has a more complex change.The research results show that the recognition and translation,to fill in more networking during design needs to consider the other side of the parameters and the effects of axial heat conduction of wall.