Abstract
Numerical investigations on flow structure and heat transfer characteristic in a heat exchanger tube fitted with U-shaped baffle are presented. The U-shaped baffle is created from the concepts of orifice and inclined baffle. The influences of the baffle height (b/D = 0.05, 0.10, 0.15, 0.20 and 0.25) and flow attack angle (α = 20°, 30° and 45°) of the U-shaped baffle on heat transfer, pressure loss and thermal performance are considered. The finite volume method with SIMPLE algorithm is selected to solve the present problem. The numerical results are reported in terms of flow visualization and heat transfer behavior. The performance analysis for the tube heat exchanger inserted with the U-shaped baffle is also reported. As the numerical result, it is found that the insertion of the U-shaped baffle help to improve the heat transfer rate and thermal performance higher than the smooth tube with no baffle. The increments of heat transfer rate and pressure loss are around 1–8.7 and 1–29 times over the smooth tube, respectively. Additionally, it is detected that the 45° U-shaped baffle with the BR = 0.2 gives the highest thermal enhancement factor around 2.9 at the highest Reynolds number, Re = 1200.
Highlights
The thermal performance improvement in various types of the heat exchanger is frequently found in many industries
The article presents the numerical studies on flow and heat transfer characteristics in a circular tube heat exchanger inserted with the U-shaped baffle
The effects of height and flow attack angle for the U-shaped baffle on heat transfer, pressure loss and thermal performance are considered at laminar regime, Re = 100-1200
Summary
The thermal performance improvement in various types of the heat exchanger is frequently found in many industries. The performance analysis of the tube heat exchanger inserted with the U-shaped baffle on the Nusselt number ratio, friction factor ratio and thermal enhancement are reported as Figs. The addition of the U-shaped baffle in the tube heat exchanger provides higher heat transfer rate, pressure loss and thermal performance than the smooth circular tube with no baffle. Performance analysis: (a) Nu/Nu0 Vs Re, (b) f/f0 Vs Re and (c) TEF Vs Re. Considering at similar blockage ratio, the enhancements of heat transfer rate and friction loss are detected when increasing the flow attack angle of the Ushaped baffle, except for BR = 0.05. The heat transfer rate and friction loss are around 1–8.7 and 1–29 times above the smooth tube, respectively, depended on flow attack angle, blockage ratio and Reynolds number. The thermal enhancement factor is found to be around 1–2.9 depended on the blockage ratio, flow attack angle and Reynolds number
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