汽-水换热器内流体诱导振动强化传热试验

提出利用换热器内流体诱导振动实现强化传热的方法 .在利用传热表面振动提高对流换热系数的同时 ,利用振动变形减少积垢 ,降低污垢热阻 ,实现了复合强化传热 .对管内外流体流动诱导弹性管束的振动特性、强化传热特性和污垢特性进行了试验研究

EXPERIMENTAL INVESTIGATION OF HEAT TRANSFER ENHANCEMENT BY FLOW INDUCED VIBRATION IN STEAM-WATER HEAT EXCHANGERS

A new concept of the compound heat transfer augmentation by flow-induced vibration was put forward in steam-water heat exchangers. The vibration of heat transfer surface can increase the heat transfer coefficient.In the meantime, the vibration of the tubes can also remove the fouling adhered to the tube surface easily, and therefore, the fouling thermal resistance can be decreased. Experiments were carried out on the vibration and heat transfer characteristics of the elastic tube bundles used in steam-water heat exchanger. Experimental results showed that the tube bundles vibrated mainly at its lower natural frequencies in crossflow, whereas, for the in-tube flow, they vibrated randomly at a wide range of frequencies. Experiments of heat transfer characteristics revealed that the convective heat transfer coefficient of the outside tube was greatly raised while that of the inside tube rose slightly. Generally, the outside average convective heat transfer coefficient for the elastic tube bundles is five times that of the fixed tube bundles at the same Re .The mechanism of reduction of fouling thermal resistance has been analyzed.