Effects of Jet Nozzle Circumferential Position and Vortex Chamber Draft Angle on the Flow and Heat Transfer Characteristics of Vortex Cooling[J]. 2018, 52(11): 65-72.
DOI:
Effects of Jet Nozzle Circumferential Position and Vortex Chamber Draft Angle on the Flow and Heat Transfer Characteristics of Vortex Cooling[J]. 2018, 52(11): 65-72.DOI: 10.7652/xjtuxb201811010.
Effects of Jet Nozzle Circumferential Position and Vortex Chamber Draft Angle on the Flow and Heat Transfer Characteristics of Vortex Cooling
The effects of jet nozzle circumferential position and vortex chamber draft angle were numerically investigated based on the vortex cooling model suitable for blade leading edge. With the verified turbulence model
the CFD method was carried out to analyze and compare the flow and heat transfer behaviors of different cooling models. Results showed that high speed rotational flow is formed by the cooling air injected from the nozzles. The cooling air's three-dimensional streamlines first shrink and then expand radially along the axial direction. When the jet nozzle circumferential position changes
the relative position of high speed vortex region and low speed vortex region may also change
and the position of high Nusselt number region alters circumferentially. When inlet is on the shroud side
the area of high speed vortex region is enlarged and the area of low speed vortex region is contracted with the vortex chamber draft angle. Moreover
the pressure coefficient decreases as the vortex chamber draft angle increases. When the vortex chamber draft angle is positive
the pressure coefficient increases along the axial direction; when the vortex chamber draft angle is negative
the pressure coefficient decreases along the axial direction. If the vortex chamber draft angle is set -1° as the reference
when the vortex chamber draft angle is increased to 1°
the heat transfer intensity is increased by 9.1%
the wall heat flux is increased by 8.4%
the friction factor is decreased by 4.1% and the comprehensive thermal performance coefficient is increased by 8.8% compared with their corresponding reference values. The flow and heat transfer characteristics of the vortex cooling under different geometrical parameters investigated in this paper
and aims to provide references for designing practical blade tip cooling structures.
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