Heat transfer and hydraulic resistance of a flat channel with discrete wall roughness in the form of inclined trench dimples

An experimental study of heat transfer and hydraulic losses in a channel with one wall being a surface with trench dimple was carried out. The working surface had four rows of dimples located alternately at angles of 45° and −45° to the channel axis. In the laminar regime, the transfer of heat and the losses of pressure turned out to be close to the parameters of a smooth channel. In the turbulent regime, a 1.5-fold enhancement of heat transfer with respect to the transfer of heat in a smooth channel was obtained. The dependence of the increase in pressure losses on the Reynolds number qualitatively agreeing with the dependence for the channels with sandy roughness is obtained.