Development And Research Of Efficient Numerical Simulation Method For Twophase Flow And Experimental Platform For Condensation Heat Transfer

Condensation heat transfer is widely existed in air-conditioners,heat pumps and other kinds of heat-exchanging devices.However,the thermal resistance of the refrigerants on the condensing side is always the main one of these devices.In order to improve the efficiency of heat-exchanging devices and use energy effectively,the research on condensation heat transfer of refrigerants is becoming more popular.With the exploitation of new energy and the rising of recycling waste heat in all industries,the condensing tube in heat-exchanging devices starts to develop from small diameter to large ones.Therefore,it is necessary to research on two-phase flow and the mechanism of condensation heat transfer in large diameter condensing tubes.In order to research on condensation heat transfer of refrigerants in large diameter condensing tubes,an efficient numerical simulation method of two-phase flow called ‘VOSET+IDEAL method combined with BCTBi-CGSTAB algorithm' is built on the aspect of numerical simulation in this paper,aiming at the long time-consuming procedure of simulating the condensation heat transfer process,especially when simulating phase interface distribution and the flow near it.It is proved that the VOSET+IDEAL method is accurate and effective through three classic examples comparing VOSET+IDEAL method with VOSET+ SIMPLER and VOSET +SIMPLEC method.And then,through the same examples,it is also proved that the BCT-Bi-CGSTAB algorithm is superior compared with ADI and BCT-ADI when combined with the VOSET+IDEAL method.Finally,it is concluded that the ‘VOSET+ IDEAL method combined with BCT-Bi-CGSTAB algorithm' is doable and efficient.On the aspect of experimental research,a visual experimental platform for condensation heat transfer of refrigerants is established,aiming at large diameter condensing tubes,including the designing and selecting of each unit in the platform,calculating the on-way resistance and so on.The pressure experiment conducted on the platform shows that the platform is pressure-proof and gas-tight,besides,all of the sensors on the platform work normally.Based on the conducted experiment,the experimental platform is verified through a single-phase experiment.It is proved that the experimental platform established in this paper operates stably and the collected data is accurate and reliable.The research achievements above could set a strong foundation for the research on two-phase flow distribution and the mechanism of condensation heat transfer in large diameter condensing tubes and enhanced ones both numerically and experimentally.