Theoretical And Experimental Study On Integrated Micro-Channel Heat Exchanger

Compared with conventional heat exchangers, micro-channel heat exchangers have advantages of compact size and higher heat transfer coefficient, so have become a global hot research topic in recent years. In the aerospace field, owning to the rapid increase of released heat in the airborne system, severe restriction on the size and weight, the micro-channel heat exchanger has gradually become the mainstream cooling method of future aircrafts.In this paper, a theoretical and experimental study on integrated micro-channel heat exchanger has been conducted based on the research progress and basic characteristics of heat transfer and heat storage of the micro-scale heat exchanger. The following appeals are the specific work and the main achievements:1. The heat transfer between water and propanediol was studied via the theoretical analysis and numerical calculation method. The CFD method was employed to explore the relationship among resistance, the heat transfer capacity and flow rate. The results reveal that that with the increase of the flow rate, pressure drop rises sharply the integrated micro-channels heat exchanger, the heat transfer coefficient increases too.2. A two-dimensional water-paraffin physical model of micro-channel heat storage unit was set up and the CFD method was used to investigate the temperature variation of the phase change materials and the relationship between liquid rate and time was also observed. It proves that the micro-channel heat storage unit is more stable and efficient compared with the conventional concentric sleeve regenerator.3. A test apparatus of heat transfer between water and water was constructed. Then the pressure drop and temperature curve, along with the change of flow are mapped, and the conclusion of test is compared with that of numerical simulation. Results show that experimental data of laminar region flow and the numerical simulation results based on the continuum hypothesis can be a good match, under the condition of meet the pressure loss, integrated micro-channel heat exchanger has several times higher heat transfer performance than ordinary heat exchanger.4. We process the integrated microchannel test pieces on the basis of the heat transfer test apparatus, and set up an experiment table of thermal storage between water and paraffin, then temperature curve along with the change of time are mapped, and the conclusion of test is compared with that of numerical simulation. Results show that experimental data verifies the conclusion of numerical simulation well. Temperature of the PCM and water almost synchronous rise in integrated microchannel regenerator, which is close to the ideal state. Ordinary regenerator is inferior by comparison in thermal efficiency to the integrated micro-channel regenerator.The research achievements can provide referenced basis for the design, manufacture and apply in the field of aerospace of integrated microchannel heat exchanger and regenerator.