Heat transfer enhancement by V-shaped protrusions on jet plate under different crossflow conditions

This paper studies the effect of jet plate V-shaped protrusions (VP) on impingement cooling at the crossflow-to-jet mass flow ratio (CMFR) ranging from 0 to 0.5. The effects of location (L), height (H), open angle (theta) of VP and crossflow-to-jet temperature ratio (TR) are discussed. From results, compared with Baseline case (impingement cooling without VP), all VP cases can enhance heat transfer (Nuave), although friction loss coefficient (f) also increase, thermal performance factor (TPF) are improved. When L varies from 1.5D to 3.0D, VP case with L of 1.5D has the highest Nuave and f, and at CMFR of 0.5, it owns the highest TPF of 1.081. When H increases from 0.1D to 0.4D, Nuave, f and TPF gradually increase. However, when H varies from 0.4D to 0.5D, only Nuave and f also increase, TPF increases only at CMFR ranging from 0.4 to 0.5. Besides, with the increase of theta, Nuave, f and TPF increase, and VP case with the theta of 110 degrees always obtains the highest TPF. At CMFR of 0.5, TPF is up to 1.098. Finally, for impingement cooling with/without VP, as TR increases, the heat transfer always decreases.