Analysis of thermohydraulic efficiency increase during transformer oil flow in a minichannel with a single-row package of spherical and oval dimples at a heated wall

Heat transfer intensification for laminar and turbulent flows in a narrow channel with one-row oval dimples

“…The integral flow and heat transfer characteristics are calculated as in [6,7,20,21,[23][24][25][26]. Thus, ζ (the coefficient of hydraulic loss between the two selected successive channel cross sections) is determined from the drop of the total pressure.…”

“…However, when the insert size is small, it is pref erable to call these dimples based on the spot shape: oval dimples [19]. A significant advantage of isolated oval dimples in comparison with spherical ones with respect to the thermal and thermohydraulic efficiencies was demon strated in [19][20][21][22][23].…”

“…The asymptotic characteristics of the flow and heat exchange in the channel with dimples are also analyzed based on the periodic boundary condi tions in an isolated repeating module containing one dimple [28][29][30][31]. It should be emphasized that recently interest in one row reliefs of dimples, both spherical [26,32,33] and oval [21][22][23], has increased because of studies on heat transfer intensification in micro channels with dimples.…”