scholarly journals Steady-State Fluid-Solid Mixing Plane to Replace Transient Conjugate Heat Transfer Computations during Design Phase

2021 ◽  
Vol 6 (2) ◽  
pp. 6
Author(s):  
Lucian Hanimann ◽  
Luca Mangani ◽  
Ernesto Casartelli ◽  
Elmar Gröschel ◽  
Magnus Fischer
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Conjugate Heat Transfer ◽  
Pressure Ratio ◽  
Jet Impingement ◽  
Rotating Disk ◽  
Propagation Time ◽  
Back Side ◽  
Thermal Loads ◽  
Physical Point

The demand for increased turbomachinery performance, both, towards higher pressures and temperatures, leads to high thermal-loads of specific components and can critically affect mechanical integrity. In the particular case of rotating-disk configurations, like the back-side of wheels or in cavities, a very efficient way for cooling is jet impingement. An example for this situation are high pressure-ratio turbochargers, where cooling of the impeller disk (back wall) is introduced to achieve tolerable thermal loads. From the physical point of view, jet impingement on a rotating wall generates an unsteady heat transfer situation. On the other end, accurate values of time-averaged temperatures would be sufficient for design purposes. In general, obtaining circumferentially time-averaged solutions requires transient analysis of the conjugate heat transfer (CHT) process to account for the mean effect of jet cooling on solids. Such analysis is computationally expensive, due to the difference in information propagation time-scale for the solid and the fluid. In this paper, a new approach to directly compute circumferentially time-averaged (i.e., steady-state) temperature distributions for rotating-disk CHT problems is presented based on an adaption of the well known fluid-fluid mixing plane approach.

Numerical Simulation of Transient Thermal Transport on a Rotating Disk Under Partially Confined Laminar Liquid Jet Impingement

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Jorge C. Lallave ◽  
Muhammad M. Rahman
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Finite Thickness ◽  
Jet Impingement ◽  
Rotating Disk ◽  
State Condition ◽  
Bottom Surface ◽  
Liquid Jet ◽  
Steady State Condition ◽  
Solid Disk

Abstract This paper considers the transient conjugate heat transfer characterization of a partially confined liquid jet impinging on a rotating and uniformly heated solid disk of finite thickness and radius. A constant heat flux was imposed at the bottom surface of the solid disk at t=0, and heat transfer was monitored for the entire duration of the transient until the steady state condition was reached. Calculations were done for a number of disk materials using water as the coolant, covering a range of Reynolds numbers (225–900), Ekman numbers (7.08×10−5−∞), nozzle-to-target spacing (β=0.25–1.0), confinement ratios (rp/rd=0.2–0.75), disk thicknesses to nozzle diameter ratios (b/dn=0.25–1.67), and solid to fluid thermal conductivity ratios (36.91–697.56). It was found that a higher Reynolds number decreases the time to achieve the steady state condition and increases the local and average Nusselt number. The duration of the transient increases with the increment of the Ekman number and disk thickness, and the reduction in the thermal diffusivity of the disk material.

Jet Cooling at the Rim of a Rotating Disk

1979 ◽  
Vol 101 (1) ◽  
pp. 68-72 ◽  
Author(s):  
D. E. Metzger ◽  
W. J. Mathis ◽  
L. D. Grochowsky
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Jet Impingement ◽  
Rotating Disk ◽  
Impinging Jets ◽  
Turbine Engine ◽  
Transfer Rates ◽  
Jet Cooling ◽  
Geometric Conditions ◽  
Face Contour

Results are presented from an experimental study conducted to measure heat transfer rates at the rim of a rotating disk convectively cooled by impinging jets. The disk face contour radially inward from the rim is varied to simulate the geometric conditions found on gas turbine engine rotors. Heat transfer rates are found to be relatively unaffected by impingement for jet flowrates less than the order of one-tenth the disk pumping flow. Disk pumping flows are evaluated through the use of an analysis which accounts for the presence of the disk hub. At larger jet flowrates, heat transfer rates increase strongly with increasing jet flow, reaching two to three times the no-impingement values at jet flowrates approximately equal to the pumped flow. All the heat transfer results, both with and without jet impingement, are essentially unaffected by changes in the disk face contour.

Numerical and Experimental Study of Flow and Convective Heat Transfer on a Rotor of a Discoidal Machine with Eccentric Impinging Jet

2019 ◽  
pp. 1-29
Author(s):  
Chadia Haidar ◽  
Rachid Boutarfa ◽  
Mohamed Sennoune ◽  
Souad Harmand
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Steady State ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Air Flow ◽  
Impinging Jet ◽  
Rotating Disk ◽  
Reynolds Numbers ◽  
Air Jet

This work focuses on the numerical and experimental study of convective heat transfer in a rotor of a discoidal the machine with an eccentric impinging jet. Convective heat transfers are determined experimentally in steady state on the surface of a single rotating disk. The experimental technique is based on the use of infrared thermography to access surface temperature measurement, and on the numerical resolution of the energy equation in steady-state, to evaluate local convective coefficients. The results from the numerical simulation are compared with heat transfer experiments for rotational Reynolds numbers between 2.38×105 and 5.44×105 and for the jet's Reynolds numbers ranging from 16.5×103 to 49.6 ×103. A good agreement between the two approaches was obtained in the case of a single rotating disk, which confirms us in the choice of our numerical model. On the other hand, a numerical study of the flow and convective heat transfer in the case of an unconfined rotor-stator system with an eccentric air jet impinging and for a dimensionless spacing G=0.02, was carried out. The results obtained revealed the presence of different heat transfer zones dominated either by rotation only, by the air flow only or by the dynamics of the rotation flow superimposed on that of the air flow. Critical radii on the rotor surface have been identified

Conjugate Heat Transfer in a Rotor-Stator System With Through-Flow

2002 ◽  
Author(s):  
Reby Roy ◽  
B. V. S. S. S. Prasad ◽  
S. Srinivasa Murthy
Keyword(s):  
Heat Transfer ◽  
Boundary Layer Thickness ◽  
Conjugate Heat Transfer ◽  
Rotating Disk ◽  
Thermal Boundary Layer Thickness ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Nusselt Numbers ◽  
Commercial Code ◽  
Through Flow

The conjugate heat transfer in a stationary cylindrical cavity with a rotating disk and fluid through-flow is analysed at various rotational speeds ranging from 10000 to 50000 rpm by using a finite volume commercial code. The numerical model and code are validated for a problem, which involves rotation and fluid through-flow. A reduction of the thermal boundary layer thickness and increase in the heat transfer coefficients are observed with increase in the rotational speed. Marked differences are noticed between the Nusselt numbers obtained from the conjugate and constant temperature analyses.

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