Heat transfer enhancement within an internal passage by combinations of ribs and suction holes

The experimental investigations of heat transfer characteristics of internal passage with rib and suction hole have been conducted.The transient thermochromic liquid crystal technique was used to measure the heat transfer coefficients in the case that Reynolds number(based on average mainstream velocity and hydraulic diameter of the internal passage) changed from 20 000 to 80 000 and suction ratios(Br) changed from 0.30 to 0.60.The results show that heat transfer is firstly enhanced near suction holes.Also,the heat transfer coefficients of upstream ribs are larger than those downstream.Secondly,heat transfer distribution of the wall is not significantly affected by changes in suction ratios and Reynolds number.Thirdly,within the range of parameters,changes in suction ratios do not significantly affect the magnitudes of average heat transfer coefficients and heat transfer enhancement.However,the value of average heat transfer coefficients increases as Reynolds number increases,but the enhancement factor distributions are found to be a weak function of the Reynolds number.