Heat Transfer Characterization Inside a Rotating Rib Roughened Cooling Channel With Multiple Heated Walls

2021 ◽  
Author(s):  
Andrea Lorenzon ◽  
Luca Casarsa ◽  
Elia Cucit
Keyword(s):  
Heat Transfer ◽  
Cooling Channel ◽  
Rib Roughened

Investigation of the Conjugate Convective-Conductive Thermal Behavior of a Rib-Roughened Internal Cooling Channel

2004 ◽  
Author(s):  
Roberto Fedrizzi ◽  
Tony Arts
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Thermal Behavior ◽  
Large Scale ◽  
Internal Cooling ◽  
Cooling Channel ◽  
Heat Flux Distribution ◽  
Metallic Wall ◽  
Scaled Models ◽  
Rib Roughened

The proposed contribution concerns an experimental investigation of the conjugate thermal behavior of a rib-roughened cooling channel. Previous investigations mainly were focused on the convective aspects of the heat transfer; the scaled models were made of low conductivity material and the heat conduction was not representative of the behavior inside a real metallic airfoil. To overcome this limitation, a large-scale facility with a metallic ribbed wall was designed and tested. Infrared thermography was used to measure the temperature distribution on the wetted surface. Dedicated software was developed to correct the temperature field distortions and to apply the radiation-temperature calibration. The convection coefficient was calculated as a function of the measured wall temperature and computed wall heat flux. The code FLUENT® was used to solve the energy equation into the metallic wall, providing the surface heat flux distribution. The complex contribution of the ribs, in terms of heat transfer, was highlighted.

Experimental Investigation of the Aerothermal Performance of a High Blockage Rib-Roughened Cooling Channel

2005 ◽  
Vol 127 (3) ◽  
pp. 580-588 ◽  
Author(s):  
Luca Casarsa ◽  
Tony Arts
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Flow Field ◽  
Three Dimensional ◽  
Heat Transfer Process ◽  
Cooling Channel ◽  
Complex Flow ◽  
Turbine Blade Cooling ◽  
Flow Features ◽  
Rib Roughened

The present study deals with a detailed experimental investigation of the turbulent flow inside a rib-roughened turbine blade cooling channel. The measurements are carried out in a stationary straight channel with high blockage ribs installed on one wall. The main objective is to enhance the understanding and deepen the analysis of this complex flow field with the help of highly resolved particle image velocimetry measurements. A quasi-three-dimensional view of the flow field is achieved, allowing the identification of the main time-averaged coherent structures. The combined analysis of the present aerodynamic results with available heat transfer data emphasizes the role of the mean and fluctuating flow features in the heat transfer process. In particular, the stream wise/normal to the wall component of the Reynolds stress tensor is shown to be strictly related to the heat transfer rate on the channel surfaces. A correlation to estimate the heat transfer field from the aerodynamic data is presented for the high blockage rib roughened channel flow.

Effect of Coriolis and Centrifugal Forces on Turbulence and Heat Transfer at High Rotation and Buoyancy Numbers in a Rib-Roughened Internal Cooling Channel

2004 ◽  
Author(s):  
A. K. Sleiti ◽  
J. S. Kapat
Keyword(s):  
Heat Transfer ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Internal Cooling ◽  
Cooling Channel ◽  
Centrifugal Forces ◽  
Reynolds Stresses ◽  
Rsm Model ◽  
Density Ratios ◽  
Rib Roughened

Prediction of three-dimensional flow field and heat transfer in a two pass rib-roughened square internal cooling channel of turbine blades with rounded staggered ribs rotating at high rotation and density ratios is the main focus of this study. Rotation, buoyancy, ribs, and geometry affect the flow within these channels. The full two-pass channel with bend and with rounded staggered ribs with fillets (e/Dh = 0.1 and P/e = 10) as tested by Wagner et. al [1992] is investigated. RSM is used in this study and enhanced wall treatment approach to resolve the near wall viscosity-affected region. RSM model was validated against available experimental data (which are primarily at low rotation and buoyancy numbers). The model was then used for cases with high rotational numbers (0.24, 0.475, 0.74 and 1) and high-density ratios (0.13, 0.23, and 0.3). Particular attention is given to how secondary flow, Reynolds stresses, turbulence intensity, and heat transfer are affected by coriolis and buoyancy/centrifugal forces caused by high levels of rotation and density ratios. A linear correlation for 4-side-average Nusselt number as a function of rotation number is derived.

Numerical Aero-Thermal Analysis of a Rib-Roughened Trailing Edge Cooling Channel at Different Rotation Numbers and Channel Orientations

2014 ◽  
Author(s):  
Matteo Pascotto ◽  
Alessandro Armellini ◽  
Luca Casarsa ◽  
Sebastian Spring
Keyword(s):  
Heat Transfer ◽  
Working Conditions ◽  
Turbine Blades ◽  
Thermal Characterization ◽  
Cooling Channel ◽  
Trailing Edge ◽  
Smooth Channel ◽  
Channel Orientation ◽  
Channel Configuration ◽  
Rib Roughened

The present work considers the aero-thermal characterization of a rib-roughened cooling channel for the trailing edge of gas turbine blades, and is based on previous findings from a smooth channel configuration. The passage is characterized by a trapezoidal cross section with high aspect-ratio, radial inlet flow, and coolant discharge at both model tip and trailing side, where seven elongated pedestals are installed. In this study, heat transfer augmentation is achieved by placing inclined squared ribs on the channel central portion. RANS simulations with a SST turbulence model were performed using the commercial solver ANSYS CFX®v14. The numerical tool was first validated on the available experimental data and, subsequently, its capabilities were exploited in a wider range of working conditions, namely at higher rotation speed and different channel orientation. In this way it was possible to highlight the effects that ribs and working conditions have on the development of both flow and thermal fields. The results show that rotation and channel orientation produce contrasting effects. On the rib-roughened wall, rotation/orientation generates an increase/decrease of the heat transfer; conversely, on the trailing side region rotation/orientation has a negative/positive effect on the thermal field.

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