Article

Short Communications
2016. V. 54. № 3. P. 454–456
Lemanov V.V., Terekhov V.I.
Specific features of heat transfer at the stagnation point of an impact axisymmetric jet at low Reynolds numbers
Annotation
The average and pulsating thermal characteristics at the stagnation point of a plate at inflow of an impact axisymmetric air jet have been studied. The influence of the Reynolds number $(100 < \rm Re < 12000)$ on heat transfer has been investigated for a jet flowing from a long tube (diameter $d = 5$ mm, relative length $h/d = 200$) with the output located at a distance $h/d = 20$ from the obstacle. The measurements have been carried out using a heat-flow sensor with high spatial and temporal resolutions. A nonmonotonic change in heat transfer having a maximum is found in the range $\rm Re < 4000$ (in contrast to the known monotonic increase in heat transfer). A significant increase $(200$–$600\%)$ in the Nusselt number is observed for outflow from a tube in comparison with jet outflow from a nozzle. At $\rm Re > 4000$, the difference in heat transfers for two cases of jet formation (from a tube and a nozzle) decreases asymptotically.
Article reference:
Lemanov V.V., Terekhov V.I. Specific features of heat transfer at the stagnation point of an impact axisymmetric jet at low Reynolds numbers, High Temp., 2016. V. 54. № 3. P. 454