Effects of intersection angles on flow and heat transfer in corrugated-undulated channels with sinusoidal waves

This paper reported three-dimensional numerical simulations of the steady laminar flow and heat transfer in corrugated-undulated channels with sinusoidal waves, aiming to investigate the effects of intersection angles (theta) between corrugated and undulated plate and Reynolds number (Re) on the flow and heat transfer. The simulations are conducted by using multi-channel computational domain for three different geometries. The code is validated against experimental results and then data for Nusselt number (Nu) and friction factor (f) are presented in a Re range of 100-1500, and intersection angle range of 30-150 deg. The simulation confirms the changes. of Nuu (averaged over undulated plate) and Nuc (averaged over corrugated plate) with theta representing different characteristics. As theta increases, Nu (Nuu or Nuc) is about 2-16 times higher for the corrugated-undulated configurations CP-UH1 and CP-UP1 and the concomitant f is about 4-100 higher when compared to a straight channel having square cross section. The minimum of local Nu (Nuu or Nuc) is situated at the four contact points where the top plate touches the bottom one, and the high Nu is located upstream of the crest of the conjugate duct. Performance evaluation for the CP-UH1 channel shows that the goodness factors (G) are larger than 1 with the straight channel having a square cross section as a reference, and the 30 deg geometry channel has optimal flow area goodness.