Design method for diameter of flat tubes of heat exchange device for combustion waste heat utilization

Abstract

The invention provides a design method for the diameter of flat tubes of a heat exchange device for combustion waste heat utilization. The heat exchange device comprises a heat exchange core body, theheat exchange core body is arranged in a waste gas flue, the heat exchange core body comprises the flat tubes, the flowing directions of liquids in the flat tubes are all perpendicular to the flowingdirection of waste gas, fins are arranged in the flat tubes and are used for dividing liquid flowing channels in the flat tubes into a plurality of small flowing channels, and the small flowing channels are designed by adopting the method which comprises the following steps that the distance to a waste gas inlet is set to be S, then the hydraulic diameter of the small flowing channels of the flattubes are d, d is set to be F (S), then F'(S) is less than 0, and F'(S) is the first derivative of F (S). The main reason is that the pressure required to be borne in the flat tubes is smaller and smaller in the flowing direction of the waste gas, then the hydraulic diameter can be reduced; moreover, the hydraulic radius is reduced so that the heat exchange area can be increased, and the heat exchange capacity can be improved; and therefore, through the arrangement of the characteristics, the pressure requirement can be met, and the enhanced heat transfer can be realized.

Description

technical field [0001] The invention belongs to the field of heat exchange, and in particular relates to a shell-and-tube heat exchange device for utilizing waste heat. Background technique [0002] In the past ten years, due to the shortage of energy, energy-saving work has been further carried out. Various new, energy-saving and advanced furnace types are becoming more and more perfect, and the use of high-quality insulation materials such as new refractory fibers makes the heat dissipation loss of the furnace significantly reduced. The use of advanced combustion device strengthens combustion, reduces the amount of incomplete combustion, and the air-fuel ratio also tends to be reasonable. However, the technology to reduce exhaust heat loss and recover flue gas waste heat is still not progressing fast. In order to further improve the thermal efficiency of the kiln and achieve the purpose of saving energy and reducing consumption, the recovery of waste heat from flue gas i...

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Problems solved by technology

[0007] The purpose of the present invention is to solve the problems of low heat exchange efficiency, large weight, large occupied volume, and poor high temperature resistance of existing waste heat utilization heat exchange devices, and propose a compact structure, high temperature resistance, high power density, and high heat exchange efficiency. heat exchange device

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