Lateral-flow effect on endwall heat transfer and pressure drop in a pin-fin trapezoidal duet of various pin shapes

The effects of lateral-flow ejection (0<<epsilon><1.0), pin shapes (square, diamond and circular ), and flow Reynolds number (6000<Re<40,000) on the endwall hear transfer and pressure drop for turbulent pow through a pin-fin trapezoidal duct are studied experimentally. A staggered pin ai-ray of five rows and five columns is inserted in the trapezoidal duct, with the same spacings between the pins in the streamwise and spanwise directions: S-x/d = S-y/d = 2.5. Three different-shaped pins of length from 2.5<l/d<4.6 span the distance between two endwalls of the trapezoidal duct. Results reveal that the pin-fin trapezoidal duct with lateral-pow rate of <epsilon> = 0.3-0.4 has a local minimum endwall averaged Nusselt number and Euler number for all pin shapes investigated The trapezoidal duct of lateral outlet pow only (epsilon = 1.0) has the highest endwall heat transfer and pressure drop. Moreover, the square pin results in a better heat transfer enhancement than the diamond pin, and subsequently than the circular pin. Finally, taking account of the lateral-flow rate and the pow Reynolds number, the work develops correlations of the endwall-averaged heat transfer with three different pin shapes.