为强化低温热能发电有机朗肯循环系统的传热过程,采用机械加工方法研发肋管表面似龙鳞状的新型三维外肋强化传热管即GY管。对工质R123在光管、GY管水平单管外池沸腾换热进行实验研究,在常压条件下(正常沸点为27.4℃)得到热流密度与沸腾换热系数、管内雷诺数与传热系数的关系模型。将光管管外沸腾换热系数的实验值和Cooper公式计算值进行比较可知其变化趋势一致,实验值与Cooper公式计算值的偏差小于12%;同时,得到GY管传热系数随管内雷诺数的变化规律。实验结果表明:当雷诺数在(4.9~11.5)×103范围内时,与光管比较,GY管的传热系数强化倍率为3.10~3.45。因此,GY管是一种具有优良管外沸腾换热性能的强化管,能有效强化有机工质的换热过程。
To intensify the heat transfer process in low-temperature heat driven ORC(organic Rankine cycle) systems, the novel GY tube, the three-dimensional enhanced heat transfer tube with exterior extended surface, whose finned surface looks like dragon’s scale, was developed by machining method. The exterior pool boiling heat transfer of organic fluid R123 outside separately of smooth tube and horizontally mounted single GY tube was studied experimentally. Under atmospheric condition(the normal boiling point temperature is 27.4 ℃), the relationship between boiling heat transfer coefficient and heat flux, also the relationship between overall coefficient of heat transfer and the Reynolds number of tube interior were obtained, and the tested boiling heat transfer coefficient of outside smooth pipe was compared with that estimated by Cooper formula, the maximum deviation of the experimental values from that estimated by Cooper formula is less than 12%; the overall coefficient of boiling heat transfer variation of GY tube with the Reynolds number of tube interior was also attained, The results show that when the Reynolds number is in the range of(4.9-11.5)×103 the reinforcement ratio of GY tube is about 3.10-3.45 compared with smooth tube. Therefore, the newly developed GY tube is an excellently enhanced tubes which can reinforce exterior pool boiling process, especially the boiling heat transfer process of organic fluids.