Efficient boiling enhanced heat exchange tube and manufacturing method thereof

Abstract

The invention discloses an efficient boiling enhanced heat exchange tube and a manufacturing method thereof, and belongs to the technical field of heat exchangers. The efficient boiling enhanced heatexchange tube is structurally composed of an external base tube and a tube inner wall sintered layer, wherein the tube inner wall sintered layer is a heterogeneous super-hydrophilic copper powder particle layer, and is distributed along the cross section of the base tube in a space mode that particles on the upper wall surface are thin and dense, particles on the lower wall surface are thick and sparse, and the side wall surface is uniformly changed, so that the anti-gravity migration of liquid at the bottom of the tube can be effectively realized, and the flow pattern in the tube is improved.The tube inner wall sintered layer can provide a large number of stable vaporization cores, meanwhile, tiny holes in the tube can provide large capillary force to promote liquid supplement, the dynamic behavior of steam bubbles is changed, the steam bubble separation period is shortened, the distribution in the base tube is regulated and controlled, and boiling heat exchange is effectively enhanced. The efficient boiling enhanced heat exchange tube can be applied to a medium-low temperature waste heat power generation system, an air conditioner evaporator, a groove type solar heat collectingtube and a boiler water wall, and has wide application value and social value.

Description

technical field [0001] The invention belongs to the technical field of heat exchangers, in particular to a high-efficiency boiling enhanced heat exchange tube and a manufacturing method thereof. Background technique [0002] With the development of my country's economy, energy and environmental issues, which are one of the strategic priorities of economic and social sustainable development, have attracted people's attention. The center is how to use energy rationally and comprehensively, and continuously improve energy utilization. The inverter has a wide range of applications in many fields involving energy conversion and heat transfer. Technical ideas The development of high-efficiency heat exchangers is an effective technical means to improve energy utilization efficiency, save investment costs, and realize the integrated development of industrial equipment. [0003] The evaporator is a kind of heat exchanger, which is widely used in refrigerators, air conditioners, heat p...

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Problems solved by technology

[0003] The evaporator is a kind of heat exchanger, which is widely used in refrigerators, air conditioners, heat pumps and low-grade thermal energy conversion systems. Its performance has an important impact on the reliability and economy of the system. According to the heat flow transfer formula q =h·ΔT, high heat flux often means high heat transfer temperature difference or high heat transfer coefficient, high heat transfer temperature difference is unacceptable for general industrial equipment, especially cannot meet the requirements of modern precision equipment for ambient temperature, so increase the heat transfer coefficient Be the solution to high heat flux dissipation problems

[0004] A lot of research has been carried out on improving the heat transfer coefficient in the evaporator, and a variety of tube types have been developed to enhance the heat transfer performance, such as: grooved tubes, micro-finned tubes, internally threaded tubes, ties, spirals and other tube inserts, but The above-mentioned technology still adopts the idea of ​​single-phase heat transfer. By causing swirling flow and secondary flow, the development of the boundary layer is destroyed, and the central fluid and the tube wall fluid are mixed, ignoring the characteristics of the two-phase flow itself. The two-phase flow and the The synergistic relationship between heat transfer has not been well revealed. On the other hand, the flow pattern in the tube, as a key factor affecting the phase change heat transfer, should attract the attention of the research field of enhanced heat transfer.

[0005] The heat transfer coefficient of phase change heat transfer (evaporation or condensation) is at least 1 to 2 orders of magnitude higher than that of single-phase heat transfer coefficient, which plays an important role in the utilization and conversion system of medium and low temperature heat sources, but the phase change heat transfer of organic working fluid The coefficient is relatively low, which will cause problems such as large volume and high cost of the heat exchanger. At the same time, the boiling heat transfer and flow of the organic working fluid in the heat exchanger are not coordinated. " phase distribution (such as stratified flow), the heat transfer on the upper wall is easy to deteriorate, and at the same time, a large number of liquid droplets are entrained in the core area of ​​the high-dryness annular flow pattern. If the mass flow rate of the liquid droplets returning to the wall surface cannot evaporate with the wall surface When the velocity is in equilibrium, it will cause the wall to dry out

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