A Comprehensive Empirical Correlation for Finned Heat Exchangers with Parallel Plates Working in Oscillating Flow

Abstract

Abstract:The oscillating-flow heat transfer performance in finned heat exchangers is one of the main factors affecting the working efficiency of regenerative heat engines and refrigerators. In addition to the working parameters, the geometrical parameters of finned heat exchangers are also major influencing factors. In the present study, the ratio of the heat exchanger length and hydraulic diameter is applied as an independent similarity criterion. An experimental study has been carried out with six different geometrical dimensions of finned heat exchangers with parallel plates, in order to analyze the impacts of fin length, plate spacing, and corresponding relative fluid displacement amplitude, under various working conditions. Based on 298 tested points, a comprehensive empirical correlation for the finned heat exchangers with parallel plates working in oscillating flow has been proposed, providing a relatively accurate prediction, with 98.6% of data in the ±20% deviation and 83.9% of data in the ±10% deviation, within the range discussed.

Heat Transfer Investigation of the Unsteady Thin Film Flow of Williamson Fluid Past an Inclined and Oscillating Moving Plate

“…Implanting Equation (20) in Equation (21), accumulating the similar powers of q and comparing each coefficient of q to zero, the non-linear PDE are solved with the given boundary conditions to get u 0 (y, t), u 1 (y, t), u 2 (y, t). The general solution of Equation (21) can be written as:…”

Heat Transfer Enhancement of the Air-Cooling Tower with Rotating Wind Deflectors under Crosswind Conditions

“…While extensive studies have explored air-cooled heat exchangers [4,[15][16][17][18][19][20][21] and air-cooling towers [7,[22][23][24][25][26], few have looked at air-cooling towers with rotating wind deflectors. To investigate the effects of rotating wind deflectors on the air flow and heat transfer performance in air-cooling towers, an experimental system based on a surface condenser aluminum exchanger (SCAL)-type indirect air-cooling tower has been established with a 1:100 proportional reduction according to the similarity principle, and 3-D numerical models of the prototype indirect air-cooling tower have been built.…”