배플 플레이트 크기에 따른 관내의 유체 유동 특성 및 열전달 특성에 관한 실험적 연구

Abstract

Saving energy and efficient use are required when consider environmental problem of the earth become serious gradually with limited energy resources. Specially, energy frugality style, high efficiency heat exchanger development is urgently required over industry whole by increase trend of energy consumption recently. Interest for this heat exchanger became efficiency elevation, efficiency elevation to importance subject according as making of energy frugality style device spreads since the first Oil Shock in 1973.

Elevation of the heat transfer efficiency is specially important in this high efficiency heat exchanger. To elevation of the heat transfer efficiency, in the past, used process surface channel for improve heat transfer areas and fluid characteristics but it is condition that development of shell and tube type heat exchanger is required urgently that is more high efficiency heat exchanger according to use ship and purpose.

Heat exchanger according to purpose of the use kind of fluid, number of fluid, phase of fluid , direction of flow, speed range, heat exchanger form, shape of extension surface(fin), direction, use the quality of the material, size, capacity etc. the form very many . In many case of heat exchangers two working fluids between put solid wall and heat exchange . Heat is passed in low temperature fluid passing wall surface from high temperature fluid and accompanies phase change sometimes this time.

By method for heat exchange performance elevations of heat exchanger, at first, can think increase of heat transfer area but don't satisfaction about problem of efficient space management, increase of pumping work by pressure drop etc. Need for development of high efficiency heat exchanger that prove heat passage rates of heat exchanger for solution of this problem.

In the channel flow studied purpose of engineering by many peoples for a long time. Channel that baffle plate exists is blocked fluid flow and can be detour. So fluid is stay within channel lengthen by doing blocked time. This is desirable phenomenon in place that do by purpose that heat exchange between two bodies. Also, flow that flow baffle in channel together is shape such as shell and tube heat exchanger. This does by purpose that heat exchange between flow of tube interior and external flow.

Segmental baffle is lots of stagnant field of heat areas and increase of pressure drop. Also, be apt to corrosion or pierced a hole by fouling in stagnant field.

To investigate the characteristics of fluid flow and heat transfer performance in a channel in terms of the various effects of baffle cut rate. The results show that the decrease of a baffle cut rate gives a good heat transfer enhancement. However, it also increase pressure drop.

The object of the experimental is comparing that changing Baffle cut rate, fluid velocity in the channel and changing flow temperatures, behaved experimental study to investigate fluid characteristics of interior, pressure drop characteristics and heat transfer characteristics by PIV system, numerical prediction and heat transfer experimental.

In this experimental, baffle cut rate is 30%, 40%, 50%, velocity is 0.5m/s, 1.0m/s, 1.5m/s and heat temperature is 50℃, 40℃, 30℃, cooling temperature 5℃. PIV system determine velocity characteristics, turbulent intensity, kinetic energy and pressure drop. Also, through the numerical prediction and experimental comparing and examination for heat transfer characteristics understanding.