Swirl Flow and Heat Transfer Through Square Duct with Twisted Tape Insert
In this paper, numerical predictions and experiment of characteristics of a hydrodynamic and thermally developed turbulent flow through a square duct (30×30 mm) with twisted tape inserts and with twisted tape inserts plus axial interrupted ribs are conducted to investigated regionally averaged heat transfer and friction factors. Turbulent swirl flows having Reynolds numbers ranging from 8,900 to 29,000, a rib height-to-channel hydraulic diameter (e/Dh) of 0.067, and a length-to hydraulic diameter (L/Dh) of 30, are considered. The square ribs are arranged to follow the trace of the twisted tape and along the flow direction defined as axial interrupted ribs. The twisted tape is 1.0 mm thick carbon steel sheet with diameter of 28mm, length of 900mm, and 2.5 turns. Each wall of the square channel is composed of isolated aluminum sections. Two heating conditions are investigated for test channels with twisted tape inserts and rib turbulators: (ⅰ) electric heat uniformly applied to four side walls of the square duct, and (ⅱ) electric heat uniformly applied to two opposite ribbed walls of the square channel. The correlation for friction factor and Nusselt number are derived from the predicted date. The results show that uneven surface heating enhances the heat transfer coefficient over uniform heating conditions, and significant improvements can be achieved with twisted tape inserts plus axial interrupted ribs compare to the case of twisted tape inserts.
heat transfer twisted tape swirl flow rough square duct number of heating wall friction factor
Ho-Keun Kang Soo-Whan Ahn Bachtiar-Krishna-Putra Ary Jong-Woong Choi
Research and Development Center, Korean Register of Shipping 60 Sinseongno, 23-7 Jang-dong Yuseong-g Soo-Whan Ahn, School of Mechanical and Aerospace Engineering, Gyeongsang National University, Korea Bachtiar-Krishna-Putra Ary, Department of Mechanical System Engineering, Graduate School, Gyeongsang Jong-Woong Choi, Advanced Numerical Simulation Technology, Korea
国际会议
The Fourth International Symposium on Fluid Machinery and Fluid Engineering(第四届流体机械与流体工程国际会议)
北京
英文
122-129
2008-11-25（万方平台首次上网日期，不代表论文的发表时间）