Two dimensional flow and heat/mass transfer characteristics in rectangular wavy duct with corrugation angle

2차 유동 영역에서 꺽임각 변화에 따른 주름진 사각 덕트에서의 열/물질전달 및 유동 특성

The present study investigates the two dimensional flow and heat/mass transfer characteristics of wavy duct with various corrugation angles. For the heat/mass transfer coefficients, a naphthalene sublimation technique is used. Numerical analysis and wall pressure measurement show detailed two dimensional flow features. The corrugation angles change from 145$^{\circ}$ to 100$^{\circ}$. The operating Reynolds numbers based on the duct hydraulic diameter vary from 700 to 3,000. The duct aspect ratio maintains 7.3. On the pressure wall, strong flow mixing enhances heat/mass transfer coefficients at the front position. In addition, the rear side of pressure wall, the near of peak, is affected by the acceleration and the shedding of main flow. On the suction wall, however, flow separation and reattachment lead to the valley and the peak of heat/mass transfer coefficient. Also, highly increasing boundary layer at the suction wall affects the decrease of heat/masst transfer. As decreasing corrugation angles, the spanwise average Sherwood number increases and the peak or the valley positions of the local Sherwood number are varied.