Project Summary

The objective of this two-part investigation is to provide the designers with new internal cooling data for improving the cooling performance and thermal efficiency of power generation and industrial gas turbine engines. More specifically, this investigation ventures into the heat transfer phenomenon of internal cooling channels with shaped turbulators. The research is divided into two parts: Part I - Rotating Heat Transfer and Part II - Numerical Prediction. This investigation is a collaboration between Dr. J.C. Han and Dr. H.C. Chen of Texas A&M University. This report details the first stage of this investigation, namely the rectangular channel with V-shaped rib turbulators. A more detailed breakdown of the investigation of each of the two parts follows.

Part I: Rotating Heat Transfer

The objectives of part I are to obtain experimental data from rectangular, two-pass internal cooling passages with higher aspect ratios of 2:1 and 4:1. The following parameters will be altered: (1) Surface geometry, (2) Reynolds numbers, (3) rotation number, (4) rotation angle, and (5) channel aspect ratio. Angled ribs, V-shaped ribs, and delta-shaped turbulators will be installed on the leading and trailing sides of a rectangular internal cooling passage with rotation. The ratio of inlet coolant temperature to surface temperature (TR) will be around 0.8 - 0.9. The experiments will be designed so that (a) regionally averaged heat transfer coefficients will be measured at different locations along the cooling passages with enhanced surfaces, and (b) pressure drops will be measured along the cooling passages under rotating conditions. The new heat transfer and pressure drop data will be correlated and compared with numerical predictions in part II. The existing rotating facility and instrumentation available in the Turbine Heat Transfer Laboratory of Texas A&M University will be employed for the proposed study.

Part II: Computational Study

The objectives of part II are to predict flow and heat transfer behaviors from rectangular, two-pass internal cooling passages with higher aspect ratios of 2:1 and 4:1. An ongoing Chimera Reynolds-Averaged Navier-Stokes (RANS) code together with an advanced state of the art second-order Reynolds stress (second moment) turbulence model will be used for the prediction of rotating rectangular cooling channels with angled ribs, V-shaped ribs, and delta-shaped turbulators. The present numerical model has been tested to provide much better flow and heat transfer predictions than the standard k-e turbulence model for rotating multi-pass square channels with angled ribs. The numerical predictions will be calibrated/compared with the part I-rotation heat transfer data. The ultimate goal is to predict and optimize flow and heat transfer in rotating rectangular channels with various shaped turbulators at very high Reynolds number and buoyancy parameter conditions.

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