Abstract
The present study numerically investigates thermal performance and turbulent flow characteristics of chevron-type plate heat exchangers with sinusoidal, trapezoidal, triangular, and elliptical corrugation profiles. The commercial code of ANSYS Fluent (v. 17.0) is used for computational fluid dynamics (CFD) simulation with the realizable k-ε model. In particular, we focus on the influence of configuration shape on a substantial change in flow direction near the contact point, yielding local vorticity. As a result, secondary vortical motions are observed in the flow passage with vorticity that is distributed locally and which changes near the contact point. Higher flow mixing generated and distributed by the secondary vortical motions contributes to the increase of the Colburn j-factor as well as the friction factor. The highest Colburn j-factor and friction factor are obtained for an elliptical profile, compared to other shapes, because of the increase in the vortex strength near the contact point.
Highlights
A chevron-type plate heat exchanger occupies little space and achieves better heat transfer performance than other heat exchangers because of its relatively large heat transfer area and its small corrugated gaps, which yield complex flows [1]
The present study investigates the turbulent flow and heat transfer characteristics in the plate heat exchanger using the following assumptions: there is no phase change inside the channels, the fouling effect is ignored, and all surfaces are assumed to be smooth
The secondary flow contributes to the enhancement of flow mixing. It leads to an interaction between the mean flow and the near-wall flows, improving the heat transfer performance while leading to an increase in pressure drop [25]
Summary
A chevron-type plate heat exchanger occupies little space and achieves better heat transfer performance than other heat exchangers because of its relatively large heat transfer area and its small corrugated gaps, which yield complex flows [1]. Tsai et al [10] examined the pressure drop and flow distribution in the plate heat exchanger They reported that contact points inside the flow channel divided the mean flow into two streams and caused considerable mixing that enhanced the heat transfer. Lee and Lee [14,15] investigated the unsteady flow characteristics of a plate heat exchanger by changing the chevron angle and the ratio of the chevron pitch to height For this study, they adopted a unitary cell, which is a repeated section of a flow channel. The present study aims to examine the influence of corrugation configurations such as sinusoidal, trapezoidal, triangular, and elliptical shapes on heat transfer and pressure drop characteristics of the plate heat exchanger
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