Forced Convection Heat Transfer on Heated Bottom Surface of a Cavity

Abstract

Experiments to measure the heat transfer characteristics for various cavities situated at a duct-wall were performed. Flow visualization, measurements of pressure and temperature distributions on the heated bottom surface of cavity were carried out. It was observed that the effects of main flow stream, reattachment of separated flow, and vortex flow in the cavity on heat transfer unexpectedly large. It was found that heat transfer did not always decrease monotonously with an increase of aspect (depth-width) ratio D/W, in the flow range of laminar to turbulent. Correlations between Num and Rew were made in laminar and turbulent heat transfer ranges.

Turbulent flow past a transverse cavity with inclined side walls. 2. Heat transfer

“…In [9], the varied parameter was the cavity depth H, and the governing Reynolds number was Re H = U H/ν. As the parameter H/L in previous studies took different values, the generalizing relations for the mean Nusselt numbers were also different: Nu L ∼ Re 0.5 L [6], Nu L ∼ Re 0.8 L [3,4], Nu H ∼ Re 0.8 H [9], and Nu L ∼ Re 2/3 L [2,8]. It was shown [10][11][12] that the primary vortex does not occupy the entire volume of the cavity in extended rectangular cavities with L/H 2, and the shear layer does not exert any significant effect on heat transfer.…”

“…In [2][3][4][5][6][7][8], the length of the transverse cavity L was varied, and the Reynolds number was calculated by the formula Re L = U L/ν, where U is the main flow velocity and ν is the kinematic viscosity. In [9], the varied parameter was the cavity depth H, and the governing Reynolds number was Re H = U H/ν.…”

“…Heat transfer in rectangular cavities with different aspect ratios (ratios of the cavity width to its depth) was considered in some previous papers [2][3][4][5][6][7][8][9][10][11][12][13]. In [2][3][4][5][6][7][8], the length of the transverse cavity L was varied, and the Reynolds number was calculated by the formula Re L = U L/ν, where U is the main flow velocity and ν is the kinematic viscosity.…”

Turbulent flow past a transverse cavity with inclined side walls. 1. Flow structure

“…In the circulation region, where the flow turns behind the reattachment point, however, the near-wall turbulent flow is laminarized under a favorable pressure gradient. The presence of a laminar-turbulent transition was established in [16,17] on the basis of measuring the mean heat-transfer coefficients. In the present experiments, in a square cavity of size mentioned above, the transition corresponded to the value Re H = 4.3 · 10 4 [18], i.e., the cavity flow was also turbulent in the above-given range of Reynolds numbers.…”

Numerical Study on Mixed Convection in Ventilated Cavities with Different Aspect Ratios

“…In addition, it was observed that, the higher you place the heating plate, the better the cooling. The same authors, in a later article [6], have studied the geometry with inlet and outlet along the top, with the Reynolds number Re of 1000 and 2000. This time Ri ranged from 12.5 to 200 and the oscillatory pattern of solution was confirmed.…”