新型椭圆形套管-管翅式蒸发式冷凝器研究

Study on a New Type of Annular Elliptic Finned Tube Evaporative Condenser

本文设计了一种新型椭圆形套管-管翅式蒸发式冷凝器,该冷凝器采用套管结构,制冷剂在圆型内管与椭圆形外管之间的环形区域流动,同时与内管中的冷却水、外管外的喷淋水及冷却空气进行热量交换。以北京阜通地铁站为实测地点,对位于该站的圆管-管翅式蒸发式冷凝器运行数据进行现场实测,以实测数据为基础对椭圆形套管-管翅式蒸发式冷凝器进行传热理论和机理分析,并通过Fluent数值模拟,将模拟结果与圆管-管翅式蒸发式冷凝器的实际运行数据进行对比。研究结果表明:当空气入口温度为27℃、空气流速为3~4 m/s时,椭圆形套管-管翅式换热器管外压降与圆管-管翅式换热器相比降低11.18%~14.65%;当喷淋水温度为27.5~33.5℃时,椭圆形套管-管翅式换热器出口制冷剂温度比圆管-管翅式换热器模拟值低2.66~10.21℃;当入口制冷剂温度大于44℃时,椭圆形套管-管翅式换热器出口制冷剂温度比圆管-管翅式换热器实测值低1.9~4.3℃,其总传热系数比圆管-管翅式换热器提高47.42%。

A new evaporative condenser with an annular elliptic finned tube heat exchanger(AEFTHE)was designed and theoretically analyzed in this study.The cooling water flowed inside the round inner tube,while the spray water and cooling air passed outside the elliptical outer tube.The refrigerant flowing between the inner and outer tube was simultaneously condensed by the cooling water,spray water and cooling air.The theoretical heat transfer analysis of the annular elliptic finned tube evaporative condenser was based on the in-situ measurement about the round finned tube evaporative condenser(RFTEC)in Futong Metro Station of Line 14 in Beijing.The simulation results were compared with the actual operating data of the traditional RFTEC.The result showed that the pressure drop in the AEFTHE was 11.18%to 14.65%lower than that of the round finned tube heat exchanger(RFTHE)when the inlet air temperature was 27℃and air velocity was in the range 3-4 m/s.The outlet refrigerant temperature of the AEFTHE was 2.66℃to 10.21℃lower than the simulation value of the RFTHE when the temperature of spray water was in the range 27.5-33.5℃.The outlet refrigerant temperature of the AEFTHE was 1.9℃to 4.3℃lower than the measured value of the RFTHE under the same conditions when the inlet refrigerant temperature was greater than 44℃.The total heat transfer coefficient of the AEFTHE was 47.42%higher than that of the RFTHE under the same conditions.