液轮机强化管内换热的研究

STUDY ON THE HEAT TRANSFER ENHANCEMENT BY THE HYDRAULIC TURBINE IN A TUBE

管壳式换热设备强化传热的方法之一是管内插入物。插入物的形式很多,但大多为单一的强化传热技术,不能防垢除垢。而污垢的存在却大大降低了换热设备的传热系数,增加了能量消耗。换热管内液轮机则实现了换热设备在线自动防垢除垢并强化传热。对液轮机强化管内换热进行了理论及试验研究,提供了传热和阻力的试验数据和方法,分析并得到了膜传热系数关联式。结果表明,液轮机使管内阻力损失仅有少量增加,却较为显著地强化了管内换热。即使与无垢光管对比,液轮机也有效地强化了传热。

The insert in a tube is one of the ways for heat trans- fer enhancement.But lots kind of the inserts cannot help to prevent or remove the fouling on the heat transfer surface. The heat transfer coefficient reduces and the energy consumes in- crease because of the fouling. But the hydraulic turbine in a heat exchanger tube can realize the fouling preventing on-line and enhance heat transfer. The experimental and theoretical research is made on the heat transfer enhancement by the hy- draulic turbine in a tube, and the experimental data of the fric- tion and heat transfer are presented. After the analysis of the experimental results, the dimensionless correlations of the Nusselt number are given. The results show that the heat trans- fer enhances observably while the pressure loss is little by the hydraulic turbine. Even in contrast with the tube without foul and inset, the hydraulic turbine can enhance the heat transfer.