通讯基站分离式热管换热器的传热性能实验研究

Experimental Study on Heat Transfer Performance of Separated Heat Pipe Heat Exchanger in Communication Base Station

通讯基站面临散热不均、散热系统能耗高等问题。分离式热管换热器能替代机房内空调的使用,有效减少基站散热系统能耗。分离式热管换热器传热性能的影响因素有充液率、工质类型和风量等。为了研究不同因素对换热性能的影响,通过理论计算对比分析了理论充液率和实际充液率的差异;搭建实验平台研究了不同充液率下换热器的传热性能变化规律,不同高、中温工质下换热器性能的差异以及室内外风机功率的改变对换热器性能的影响规律。研究发现:使用工质R134a时,最小充液率理论值和实际值的误差为4.74%,换热器最优充液率范围为27.1%~47.9%,且最佳充液率为31.6%,最佳充液率下换热器当量换热系数为909 W/℃;随着充液率的提升,换热器内部相变区域先增大后减小,传热形式由气态工质显热传热为主先变为工质相变潜热传热为主,而后变成液态工质显热传热为主;高温工质不适用于该分离式热管换热器,使用高温工质时,换热器内部无明显相变区域,换热器使用的工质沸点越低,相变区域越大,换热器性能越好,其最佳充液率范围也越大;随着室内、外风机功率增大,换热器性能均先迅速提升而后提升速率减缓,但蒸发器侧由于散热条件较差,提升内风机功率对系统传热性能的提升较提升外风机功率更为显著。

Communication base stations are facing the problems of uneven heat dissipation and high energy con⁃sumption of the heat dissipation systems.The separated heat pipe heat exchanger can replace air-conditioning in communication base stations and effectively reduce the energy consumption of base station heat dissipation sys⁃tems.The heat transfer performance of separated heat pipe heat exchanger is affected by factors such as filling ra⁃tio,working fluid type and air volume.In order to study the influence of different factors on heat transfer perfor⁃mance,the difference between theoretical filling ratio and the actual filling ratio was analyzed through theoretical calculation.The experimental platform was built to study the heat transfer performance of heat exchanger under dif⁃ferent filling ratios,the difference of heat exchanger performance under different high and medium temperature working fluids,and the influence of indoor and outdoor fan power change on heat exchanger performance.The study finds that when the working fluid R134a is used,the error between the theoretical value and the actual value of the minimum filling ratio is 4.74%,the optimal filling ratio range of the heat exchanger is 27.1%~47.9%,the optimal filling ratio is 31.6%,and the equivalent heat transfer coefficient of the heat exchanger under the optimal filling ra⁃tio is 909 W/℃.With the increase of filling ratio,the phase change area inside the heat exchanger increases first and then decreases,and the heat transfer form changes from sensible heat transfer of vapor working fluid to latent heat transfer of the phase change of the working fluid,and then to sensible heat transfer of the liquid working fluid.The high temperature working fluid is not suitable for the separated heat pipe heat exchanger.When using the high temperature working fluid,there is no obvious phase change area inside the heat exchanger.The lower the boiling point of the working fluid is used,the larger the phase change area,the better the performance of heat exchanger,and the larger the range of its optimal filling ratio.With the increase of power of indoor and outdoor fans,the perfor⁃mance of the heat exchanger increases rapidly and then slows down.However,due to the poor heat dissipation con⁃ditions on evaporator side,the improvement of the heat transfer performance of the system by increasing the power of internal fan is more significant than that of the external fan.