scholarly journals Simulations of Low Mach number Flows and Heat Transfer in Rotating Systems

2021 ◽  
Author(s):  
Ahmed Hodaib ◽  
Isabelle Raspo ◽  
Stéphane Viazzo ◽  
Anthony Randriamampianina
Keyword(s):  
Heat Transfer ◽  
Mach Number ◽  
Low Mach Number ◽  
Rotating Systems

Heat Transfer in Rotating Serpentine Coolant Passage With Ribbed Walls at Low Mach Numbers

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Shang-Feng Yang ◽  
Je-Chin Han ◽  
Salam Azad ◽  
Ching-Pang Lee
Keyword(s):  
Heat Transfer ◽  
Mach Number ◽  
Reynolds Numbers ◽  
Working Fluid ◽  
Transfer Coefficients ◽  
Low Mach Number ◽  
Heat Transfer Coefficients ◽  
Rotation Numbers ◽  
Wide Range ◽  
Mach Numbers

This paper experimentally investigates the effect of rotation on heat transfer in typical turbine blade serpentine coolant passage with ribbed walls at low Mach numbers. To achieve the low Mach number (around 0.01) condition, pressurized Freon R-134a vapor is utilized as the working fluid. The flow in the first passage is radial outward, after the 180 deg tip turn the flow is radial inward to the second passage, and after the 180 deg hub turn the flow is radial outward to the third passage. The effects of rotation on the heat transfer coefficients were investigated at rotation numbers up to 0.6 and Reynolds numbers from 30,000 to 70,000. Heat transfer coefficients were measured using the thermocouples-copper-plate-heater regional average method. Heat transfer results are obtained over a wide range of Reynolds numbers and rotation numbers. An increase in heat transfer rates due to rotation is observed in radially outward passes; a reduction in heat transfer rate is observed in the radially inward pass. Regional heat transfer coefficients are correlated with Reynolds numbers for nonrotation and with rotation numbers for rotating condition, respectively. The results can be useful for understanding real rotor blade coolant passage heat transfer under low Mach number, medium–high Reynolds number, and high rotation number conditions.

The generation of combustion noise by chemical inhomogeneities in steady, low-Mach-number duct flows

1980 ◽  
Vol 99 (2) ◽  
pp. 383-397 ◽  
Author(s):  
Y. L. Sinai
Keyword(s):  
Heat Transfer ◽  
Mach Number ◽  
Turbulent Flows ◽  
Low Frequency ◽  
Combustion Noise ◽  
Low Mach Number ◽  
First Order ◽  
Specific Heats ◽  
Chemically Reacting ◽  
Frequency Character

The low-frequency character of two model problems is exploited in order to illustrate the acoustic consequences of the interactions between chemically reacting (or relaxing) inhomogeneities and flames or constrictions in ducts. The monopole of the former is associated with heat transfer in a fluid which exhibits variations in its specific heats, while in the latter there is an extension of the classical phenomenon associated with the pulsations of an inhomogeneity of the fluid compressibility. This second mechanism is found to be insignificant, but the heat-conduction source is considered to be very powerful at sufficiently low Mach numbers; in fact, to first order it is independent of the flow Mach number for laminar, as well as a certain class of turbulent, flows.

Heat Transfer in Rotating Serpentine Coolant Passage With Ribbed Walls at Low Mach Numbers

2013 ◽  
Author(s):  
Shang-Feng Yang ◽  
Je-Chin Han ◽  
Salam Azad ◽  
Ching-Pang Lee
Keyword(s):  
Heat Transfer ◽  
Mach Number ◽  
Reynolds Numbers ◽  
Working Fluid ◽  
Transfer Coefficients ◽  
Low Mach Number ◽  
Heat Transfer Coefficients ◽  
Rotation Numbers ◽  
Wide Range ◽  
Mach Numbers

This paper experimentally investigates the effect of rotation on heat transfer in typical turbine blade serpentine coolant passage with ribbed walls at low Mach numbers. To achieve the low Mach number (around 0.01) condition, pressurized Freon R-134a vapor is utilized as the working fluid. The flow in the first passage is radial outward, after the 180° tip turn the flow is radial inward to the second passage, and after the 180° hub turn the flow is radial outward to the third passage. The effects of rotation on the heat transfer coefficients were investigated at rotation numbers up to 0.6 and Reynolds numbers from 30,000 to 70,000. Heat transfer coefficients were measured using the thermocouples-copper-plate-heater regional average method. Heat transfer results are obtained over a wide range of Reynolds numbers and rotation numbers. An increase in heat transfer rates due to rotation is observed in radially outward passes; a reduction in heat transfer rate is observed in the radially inward pass. Regional heat transfer coefficients are correlated with Reynolds numbers for non-rotation and with rotation numbers for rotating condition, respectively. The results can be useful for understanding real rotor blade coolant passage heat transfer under low Mach number, medium-high Reynolds number and high rotation number conditions.

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