Purpose

The purpose of this study is to analyze the thermal, hydraulic and entropy generation characteristics for laminar flow of water through a ribbed-wavy channel with the top wall as wavy and bottom wall as flat with ribs of three different geometries, namely, triangular, rectangular and semi-circular.

Design/methodology/approach

The finite element method-based numerical solver has been adopted to solve the governing transport equations.

Findings

A critical value of Reynolds number (Re_cri) is found beyond which, the average Nusselt number for the wavy or ribbed-wavy channel is more than that for a parallel plate channel and the value of Re_cri decreases with the increase in a number of ribs and for any given number of ribs, it is minimum for rectangular ribs. The performance factor (PF) sharply decreases with Reynolds number (Re) up to Re = 50 for all types of ribbed-wavy channels. For Re > 50, the change in PF with Re is gradual and decreases for all the ribbed cases and for the sinusoidal channel, it increases beyond Re = 100. The magnitude of PF strongly depends on the shape and number of ribs and Re. The relative magnitude of total entropy generation for different ribbed channels varies with Re and the number of ribs.

Practical implications

The findings of the present study are useful to design the economic heat exchanging devices.

Originality/value

The effects of shape and the number of ribs on the heat transfer performance and entropy generation have been investigated for the first time for the laminar flow regime. Also, the effects of shape and number of ribs on the flow and temperature fields and entropy generation have been investigated in detail.

中文翻译：

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带肋波状通道流动的热工水力和熵产生特性分析

目的

本研究的目的是分析水通过带肋波浪形通道的层流的热力、水力和熵产生特性，该通道的顶壁为波浪形，底壁为平面，具有三种不同几何形状的肋骨，即三角形、矩形和半圆形。

设计/方法/方法

采用基于有限元方法的数值求解器来求解控制输运方程。

发现

发现雷诺数 (Re _cri ) 的临界值，超过该临界值时，波浪形或肋波浪形通道的平均努塞尔数大于平行板通道的平均努塞尔数，Re _cri的值随着数量的增加而减小肋骨和任何给定数量的肋骨，矩形肋骨的最小值。对于所有类型的带肋波纹通道，性能因子 (PF) 随着雷诺数 (Re) 急剧下降，直至 Re = 50。对于 Re > 50，PF 随 Re 的变化是渐进的，并且对于所有带肋的情况和正弦通道，它会增加超过 Re = 100。PF 的大小很大程度上取决于肋的形状和数量以及 Re。不同肋条通道的总熵产生的相对大小随 Re 和肋条的数量而变化。

实际影响

本研究的结果有助于设计经济的热交换装置。

原创性/价值

首次研究了层流状态下形状和肋条数量对传热性能和熵产生的影响。此外，还详细研究了肋的形状和数量对流动和温度场以及熵产生的影响。