Numerical Simulation Of Pump-assisted Capillary Phase Change Loop With Matlab/Simulink

Pump-assisted capillary phase change loop is an effective and efficient two-phase heat transfer device with both aggressive and passive driven power. Compared with loop heat pipe(LHP), pump-assisted capillary phase change loop has some additional components which are the ejector, the micropump and the reservoir. The micropump is the major power of the liquid circulation loop, while the capillary power offered by the porous wick is the major power of the vapor circulation loop. The main advantages of the loop are longer heat transport distance and more robustness in the performance characteristics. In this work, the mathematical investigation of pump-assisted capillary phase change loop is discussed.This paper has introduced the main components and working principles of the loop. Evaporator is the core component whose design determines the operating characteristics of the system directly. Condenser dissipates heat to the ambient. We have “pipe-in-pipe” style condenser in this paper. The ejector here is utilized to take away the liquid condensed in the condenser I quickly and reduce the pressure in the vapor loop simultaneously, so that the vaporization temperature and the evaporator wall temperature will also be decreased. Reservoir has the extra liquid. Micropump offers the main power in the system circulation.A system-level mathematical model using Matlab/Simulink to simulate the transient performance characteristics of pump-assisted capillary phase change loop is developed and compared with experimental results in this work. The start-up process is investigated by solving a system of time-dependent ordinary differential equations based on mass and energy balance. Results show that the system can dissipate 100W(10.4W/cm2) at the evaporator wall temperature about 309.7K(36.7?) with transport distance of 1850 mm. Sink temperature has a significant effect on the operational characteristic of the loop while liquid flow rate's is so small that can be neglected. Besides, the system presents a very fast response to variable heat loads with no obvious temperature oscillation being observed. In the end, an experimental device has been established to verify the validation and reliability of the model. The simulated results agree with our experimental results very well as we expect.The numerical simulation of pump-assisted capillary phase change loop is studied which has a significant effect on the experimental investigation of the loop.