The effect of inflow conditions on the development of non-swirling versus swirling impinging turbulent jets

Heat transfer in a confined impinging jet with swirling velocity component

“…A large drop in Nusselt number values is visible at the center of the stagnation region which is a consequence of small values of the axial velocity components there. It is in accord with some of the literature data [6], even though as pointed out by [7], the flow and heat transfer characteristics show drastically different results depending on the type of swirl generators. In our case, we have used an axialflow impeller with six blades, 45…”

Impingement pressure characteristics of swirling and non-swirling turbulent jets

“…Since calculating S * involves the integration of hwi and hui profiles across the nozzle exit plane (r = 0 to R), two swirling flows with markedly different radial velocity profiles can still be described by the same S * [46]. With downstream jet development affected by the shape of velocity profile [13] and transitions into vortex breakdown not solely a function of high swirl numbers [18], an alternative approach is to derive a swirl intensity that accommodates the velocity profiles at the exit plane [47][48][49][50], as will be presented in the ensuing Section 2.6. Similarly from this context, a single swirl number may also be expressed as shown in Eq.…”

“…The wall jet region, which is further out (radially), then forms around the impingement region where the axial deceleration of the flow causes lateral spread near the surface. Although excellent historical [6][7][8][9] and recent [10][11][12][13] treatise exist on the flow field characteristics of turbulent impinging jets and the characteristics of three distinctive flow regions, relatively fewer works have attempted to resolve the pressure distribution in the stagnation and wall jet regions or the effects of relatively high swirl on the potential core. The impartation of swirl into an impinging jet further complicates the flow field with fundamental interpretation becoming more challenging if swirl is generated geometrically by means of helical inserts or guide vanes.…”

Features of heat transfer at interaction of an impact swirl jet with a dimple

“…So far, the heat transfer and the structure of flow between a swirling jet and a surface onto which this jet impinges remain poorly understood. Reported studies [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40], also few in number, show the interaction of a swirling jet with an obstacle to be a complex many-factor process. An increase in jet pre-rotation intensity enhances mixing processes in the system.…”