Experimental Research On Parallel Type Pulsating Heat Pipe

Pulsating heat pipe (PHP), as a new style and unique heat pipe, has someadvantages of simple construction, adaptable and excellent heat-transfer property.Besides, the heat transfer process contains sensible heat transfer and phase changeheat transfer. Based on all of these, the theoretical and experimental research wasadopted in this paper to investigate its heat transfer process.To conduct the experimental research in the effects of working fluid, inclinationangle, cooling water flow rate and cooling water temperature on the wall temperatureand heat transfer performance of parallel type pipe pulsating heat pipe, a parallel typepulsating heat pipe experimental equipment was built in this paper. Moreover, theeffects of inclination angle and liquid filling ratio on starting characteristic and heattransfer performance of parallel type plate pulsating heat pipe were also studied. Theresults showed that:1. Acetone and distilled water were used as the working fluids of parallel typepipe pulsating heat pipe. It was found that acetone was better than distilled water onoperation stability of PHP, but distilled water was better than acetone on heat transferlimitation under a high heating power. With the decrease of inclination angle, thestable operation power of PHP decreased, but the temperature fluctuation rangeamong different temperature metrical points and heat resistance increased; thereexisted an optimal flow rate of cooling water among different heating powers, and thehigher match between heating power and flow rate of cooling water had, the less heatresistance was; with the decrease of cooling water temperature, the heat resistance ofPHP increased but the starting power decreased.2. Acetone was used as the working fluid of parallel type plate pulsating heat pipe.With the increase of inclination angle, startup time and temperature differencebetween heating section and condensing section both decreased. The PHP had a goodoperation performance at the inclination angle from60°to90°, but the PHP cannotoperate at the inclination angle30°and45°. With the increase of inclination angle, theheat transfer quantity increased, but the heat resistance decreased. Moreover, the PHPhad the best operation performance at the inclination angle90°. The temperature stability between heating section and condensing section was good under the liquidfilling ratio from50%to70%. Besides, with the increase of the liquid filling ratio, thetemperature differences between heating section and condensing section increased.And the PHP had a better adaptability to the variation of heating power at a highliquid filling ratio. When the liquid filling ratio was70%, the heat resistance of PHPwas the smallest and the heat transfer performance was best.