Heat transfer characteristics in a channel fitted with zigzag-cut baffles

Abstract

The heat transfer characteristics were experimentally investigated in a wind channel with different types of cut baffles for heat transfer augmentation. The aim of using zigzag-cut baffles is to create 3D flow structure behind the baffles instead of transverse vortex flow leading to enhance heat transfer. In this study, 4 types of baffles were examined; conventional baffle (Rectangular cross section with no cut), baffle with rectangular zigzag-cut, baffle with triangle zigzag-cut at 45 degree and at 90 degree. All of the baffles have the same height at H = 15 mm and flow blocking area. In the experiment, the row of seven baffles was attached on the inner surface of wind channel. The effects of pitch spacing length were also investigated at baffle pitch distance P/H = 4, 6 and 8 (H: Height of baffle). The experiments were performed at constant Reynolds number (Re) of 20000. The heat transfer patterns via Thermochromic liquid crystal sheet were visualized and recorded with a digital camera. The recorded images were then analyzed with image processing technique to obtain the distribution of Nusselt number. The flow characteristics pass through the baffles were also numerically studied with CFD simulation for understanding the heat transfer characteristics. The friction losses were measured to evaluate the thermal performance for each baffle. It was found that the baffle with rectangular zigzag-cut gives the best thermal performance due to heat transfer augmentation in upstream and downstream side of baffle.

Nanofluids in Zigzag Elliptical Tube Heat Exchanger: A Design Perspective

“…In addition, finned zigzag tube demonstrates an increase of thermal performance by 59% in laminar flow regime compared to a finned straight tube [63]. Also, Nuntadusit et al [64] showed the optimum performance of rectangular zigzag-cut baffle against the rectangular cross-section with no cut and triangle zigzag-cut baffles at Reynolds number of 2×10 4 . The upstream and downstream sides of the baffle promote the efficient transfer of heat because of flow acceleration and low friction factor.…”

Characteristics of Heat Transfer and Turbulent Flow in a Baffled Pipe with Different Arrangements

“…4 and Fig. 5 show the velocity distribution along the pipe at the same value of Re =10000 and PR (1,3,5).…”

“…Fig. 14 shows the contour of the temperature of the smooth pipe and baffled pipe (arrangement 1 and 2) at the same Re=10000 and PR (1,3,5). Fig.…”

“…The characteristics of heat transfer of a tube provided with four various forms of zigzag-cut baffles were investigated by Nuntadusit et al [3]. It was discovered that the rectangular zigzag cut baffle provided the best thermal efficiency, leading to improve the transfer of thermal energy throughout the upstream and downstream sides of the baffle.…”