Oscillation Thermosyphon Heat Transfer Performance Of The Pilot Study

The thermosyphon is a heat transfer device that utilizes the phase change of working liquid in it. It has many essential characteristics that make it useful in a wide variety of applications in electronic engineering: the compact structure, the high heat thermal conductivity, the excellent isothermal property, the variability of the heat flux density, the ability to make the heat flux direction reverse, the ability to maintain constant evaporator temperature under different heat flux level, the ability to adapt the environment, etc.To better understand the operational characteristics of the thermosyphon, this paper was carried the visualization research about the characteristic of working fluid pulsation and phenomenon in the thermosyphon which constructed with glass tube. The influences of working fluid, Fill Ratio of liquid and inclination angle on the thermosyphon operating were analyzed. The starting time was longer when the Fill Ratio of liquid and inclination angle were larger. There were some differences in looped thermosyphon and unlooped thermosyphon. The starting time was longer and the vapor-fluid pulsating was fiercer of looped thermosyphon than that of unlooped thermosyphon. A secondary flow and a separate layer flow were found on the cross-section of the looped thermosyphon with alcohol working fluid and at the inclined state.The heat transfer performance of the copper-R22 thermosyphon cooled by water and air were researched under different input heat power, inclination angle and the cooled way. The whole pulsating and local pulsating in the thermosyphon were found. A lowest input heat power was needed when the thermosyphon started and the limited heat transfer rate was found under any inclination angle. When the input power increased, the time of thermosyphon pulsating starting became early and the pulsating amplitude increased. The limited heat transfer power increased with the inclination angle. When the cooled way was changed from natural air cooled to forced air cooled, the heat transfer performance was better. The looped thermosyphon has a better performance than the unlooped thermosyphon. A copper-R22 thermosyphon radiator was made and the performance test system was set up. The radiator heat transfer ability was studied under different environment and hot air temperature. The heat transfer rate increased with the drop of environment temperature and the rise of hot air temperature. The test results indicated that the copper-R22 thermosyphon radiator had a good heat transfer performance.