The research paper tends to review the effectiveness of helical coil in heat exchangers (HCHE). Heat exchanger is a device used in transferring thermal energy between two or more fluids or solid interfaces and a fluid...The research paper tends to review the effectiveness of helical coil in heat exchangers (HCHE). Heat exchanger is a device used in transferring thermal energy between two or more fluids or solid interfaces and a fluid, in solid particulates and a fluid at different temperatures and thermal contact. The author has concisely discussed the helical coil in heat exchanger at different shapes and conditions and compared the HCHE with straight tubes heat exchangers, and the factors affecting the performance and effectiveness of the helical coil heat exchanger such as the curvature ratio, and other heat exchangers. The author demonstrated that the HCHE provided more excellent heat transfer performance and effectiveness than straight tubes and other heat exchangers because of secondary flow development inside the helical tube, and heat transfer coefficient increased with an increase in the curvature ratio of HCHE for the same flow rates. The secondary flow and mass flow rates, advantage</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> and disadvantage</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> have also been reviewed. The authors back their findings with available theories. Suitable fluid should be searched for high efficiency in the helical coil.展开更多
针对矿井降温用螺旋盘管空冷器的结构特点,首次提出了完整的传热和压降计算方法,并对常用的400 k W空冷器进行优化设计。试验测试证明,采用该计算方法设计的换热器的换热性能满足要求,壳侧空气流通阻力和管内水的实测流动阻力分别比计...针对矿井降温用螺旋盘管空冷器的结构特点,首次提出了完整的传热和压降计算方法,并对常用的400 k W空冷器进行优化设计。试验测试证明,采用该计算方法设计的换热器的换热性能满足要求,壳侧空气流通阻力和管内水的实测流动阻力分别比计算值平均高出14.4%和6.9%,根据试验测试结果,提出了提高设计精度的方法。展开更多
在系统压力P=412~850 k Pa,过冷度?Tsub=4.7~15.0℃,热通量q"=0.11~10.90 k W·m^(-2),质量流量G=147.5~443.7 kg·m^(-2)·s-1的条件下,对立式和卧式螺旋管内R134a过冷流动沸腾起始点特性进行了实验研究。研究结果表...在系统压力P=412~850 k Pa,过冷度?Tsub=4.7~15.0℃,热通量q"=0.11~10.90 k W·m^(-2),质量流量G=147.5~443.7 kg·m^(-2)·s-1的条件下,对立式和卧式螺旋管内R134a过冷流动沸腾起始点特性进行了实验研究。研究结果表明:当实验系统参数相同时,立式和卧式螺旋管内过冷沸腾起始点的热通量基本相同,但是立式螺旋管内过冷沸腾起始点壁面过热度小于卧式螺旋管;过冷沸腾起始点的热通量、壁面过热度随着过冷度和质量流量的增大而增大,但随着压力、螺旋直径的增大而减小。通过无量纲分析对实验数据进行非线性拟合,发展了适用于螺旋管过冷沸腾起始点的关联式。展开更多
文摘The research paper tends to review the effectiveness of helical coil in heat exchangers (HCHE). Heat exchanger is a device used in transferring thermal energy between two or more fluids or solid interfaces and a fluid, in solid particulates and a fluid at different temperatures and thermal contact. The author has concisely discussed the helical coil in heat exchanger at different shapes and conditions and compared the HCHE with straight tubes heat exchangers, and the factors affecting the performance and effectiveness of the helical coil heat exchanger such as the curvature ratio, and other heat exchangers. The author demonstrated that the HCHE provided more excellent heat transfer performance and effectiveness than straight tubes and other heat exchangers because of secondary flow development inside the helical tube, and heat transfer coefficient increased with an increase in the curvature ratio of HCHE for the same flow rates. The secondary flow and mass flow rates, advantage</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> and disadvantage</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> have also been reviewed. The authors back their findings with available theories. Suitable fluid should be searched for high efficiency in the helical coil.
文摘针对矿井降温用螺旋盘管空冷器的结构特点,首次提出了完整的传热和压降计算方法,并对常用的400 k W空冷器进行优化设计。试验测试证明,采用该计算方法设计的换热器的换热性能满足要求,壳侧空气流通阻力和管内水的实测流动阻力分别比计算值平均高出14.4%和6.9%,根据试验测试结果,提出了提高设计精度的方法。
文摘在系统压力P=412~850 k Pa,过冷度?Tsub=4.7~15.0℃,热通量q"=0.11~10.90 k W·m^(-2),质量流量G=147.5~443.7 kg·m^(-2)·s-1的条件下,对立式和卧式螺旋管内R134a过冷流动沸腾起始点特性进行了实验研究。研究结果表明:当实验系统参数相同时,立式和卧式螺旋管内过冷沸腾起始点的热通量基本相同,但是立式螺旋管内过冷沸腾起始点壁面过热度小于卧式螺旋管;过冷沸腾起始点的热通量、壁面过热度随着过冷度和质量流量的增大而增大,但随着压力、螺旋直径的增大而减小。通过无量纲分析对实验数据进行非线性拟合,发展了适用于螺旋管过冷沸腾起始点的关联式。
