The Technical Research Of Applying Self-scillation To Shell And Tube Heat Exchanger For Heat Transfer Enhancement

Aiming at the problem that without sourcework pulse heat transfer enhancement of shell and tube heat exchanger in industry, based on numerous literatures, a series of different self-oscillation chamber were designed to realize without sourcework heat transfer enhancement of shell and tube heat exchanger. Pulse heat transfer enhancement mechanism and self-oscillation manchanism were analyse in theory: the flow field and temperature field in the tube were effected by pulse flow and the factors of the pulse heat transfer enhancement were effected; the instability of cut layer were considered the determinant of formming self-oscillation; the calculate formula of chamber inherent frequency were educe from the hydro-meshwork theory model on water and electricity assimilate. The flow field of self-oscillation chamber were calculated by FLUENT instability flow model, the self-osillation pulse manchanism were open out. The flow fields of chamber were analyse by FLUENT, we can educe the chamber structure parameter is important to the forming of self-oscillation and the operation parameters direct effect the out kinetic energy. The optimize extension of the chamber structure parameter were educed by a lot of numerical value simulation, hut angle: 120 degree; the ratio of chamber diameter and out diameter D_c/d₂: 4～7; the ratio of out diameter and portal diameter d₂/d₁ : 2～2.3; the ratio of chamber length and diameter L_c/D_c: 0.4～0.7. Three terms were need by chamber structure to form oscillation: The chamber has the reasonable ratio of legth and diameter, out-mouth have well transflux speciality and potal have enough kinetic energy. We gained from the test research of applying self-oscillation to heat transfer enhancement: the chamber can form pulse at stated structure and operation parameters; the effect of heat exchange coefficient is different when the ratios of chamber length and diameter at the same Re, there is a optimize ratio, the resistance losing will be increase along with Re increase. Experimental result was of great significance to self-oscillation chamber design and industrial application.