重力式热管串联运行的性能研究

EXPERIMENTAL INVESTIGATION ON PERFORMANCE OF SERIES-WOUND THERMOSYPHONS

对一种用于太阳能-土壤源热泵地板采暖系统中的碳钢／水重力式热管进行了实验研究。该热管全长0．8m，内外径分别为12mm和15mm。蒸发段采用水加热，冷凝段采用风冷。在不同的串联方式、倾角（-2°～9°）、热水温度（40～60℃）、热水流量（0．1～0．3m^3／h）及蒸发段长度（30～180mm）下进行了串联热管的性能实验。实验结果表明：串联热管的传热功率和壁面温度均随供水温度和水流量的提高而持续增长，随倾角和蒸发段长度的增加而先增长后下降；串联热管在倾角为30°～40°、热水温度为60℃、热水流量为0-3m^3／h、蒸发段长度为120mm、D型串联的条件下运行最佳。根据实验现象和数据分析了不同条件下串联热管的传热机理，给出了串联热管的工作特性。

The performance of a carbon-steel/water thermosyphon was studied for applying under-floor heating system with solar-ground source heat pump in low-temperature. The carbon-steel tube is 0.8m long, and its inner and outer diameters are 12mm and 15mm, respectively. Its evaporator section is heated by hot water while its condenser section is cooled by air. Experimental investigation has been done to find out the effect of inclination angle（ - 2° - 90°）, evaporative length （30～180mm）, temperature（40-60℃） and flow rate（0.1～0.3 m^3/h） of hot water, and series-wound type（A, B, C, D） on thermal performance of series-wound thermosyphons. Experimental results indicate that heat transfer rate and surface temperature of series-wound thermosyphons increase with the rise of hot water temperature and flow rate. With increasing inclination angle and evaporative length, heat transfer rate and surface temperature increase at first, attain their maximums, and then start to decline. The optimal operating condition of series-wound thermosyphons is the evaporative length of 120mm, inclination angle of 30°～40°, hot water temperature of 60℃, flow rate of 0.3m^3/h, and series- wound type of D. Based upon experimental phenomena and data, the heat transfer mechanism of series-wound thermosyphons and their operating performance were discussed.