Influences of Flow Attack Angles and Flow Directions on Heat Transfer Rate, Pressure Loss, and Thermal Performance in Heat Exchanger Tube with V-Wavy Surface

Amnart Boonloi,Withada Jedsadaratanachai

doi:10.1155/2018/5848290

Abstract

Numerical investigations on flow and heat transfer characteristics in the heat exchanger tube with the V-wavy surface are presented. The finite volume method with the SIMPLE algorithm is selected to solve the present problem. The effects of flow attack angles (α = 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, and 60°) and flow directions (V-tip pointing downstream known as “V-Downstream” and V-tip pointing upstream known as “V-Upstream”) for the V-wavy surface on flow and heat transfer patterns are considered for both laminar and turbulent regions. The laminar regime is studied in the range Re = 100–1200, while the turbulent region is investigated in the range Re = 3000–10,000. The mechanisms on flow and heat transfer in the test section are reported. The numerical results reveal that the V-wavy surface changes the flow structure in the test section. The vortex flow is produced by the V-wavy surface. The vortex flow disturbs the thermal boundary layer on the heat transfer surface that is the reason for heat transfer and thermal performance enhancements. The optimum flow attack angles of the V-wavy surface for laminar and turbulent regimes are concluded.

Highlights

Many researchers had analyzed the augmentation of the heat transfer rate in the heat exchanger by using turbulators
Chen et al [1] numerically and experimentally investigated the flow and heat transfer of an impingement jet array with V-ribs on the target and impingement plates. e three different cases V-ribs on both the impingement and target plates, V-ribs placed on the impingement plate, and V-ribs placed on the target plate were compared for Modelling and Simulation in Engineering
Deo et al [3] studied the heat transfer, pressure loss, and thermal performance in a rectangular duct placed with multigap V-down ribs combined with staggered ribs on one wall. e influences of pitch-toheight ratio, rib height-to-hydraulic diameter ratio, and flow attack angle on flow and heat transfer were considered for Re 4000 12,000. ey summarized that the maximum augmentations on the Nusselt number and thermohydraulic performance were around 3.34 and 2.45 times, respectively

Summary

Research Article

Influences of Flow Attack Angles and Flow Directions on Heat Transfer Rate, Pressure Loss, and Thermal Performance in Heat Exchanger Tube with V-Wavy Surface. Jedsadaratanachai and Boonloi [22] numerically investigated the effects of wavy height and wavy thickness for the V-wavy plate in a round tube heat exchanger on heat transfer rate, friction loss, and thermal performance. E length periodic module of the circular tube equipped with the V-wavy surface is created around D. e influences of the flow attack angles (α 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, and 60°) and wavy surface arrangements (V-Downstream and V-Upstream) on heat transfer and pressure loss are considered for both laminar (Re 100– 1200) and turbulent (Re 3000–10,000) regimes.

Nux hx

Insulator and no slip wall condition

TEF TEF