Systematic experiments are conducted to measure heat transfer enhancement and pressure loss characteristics on a square channel (simulating a gas turbine blade cooling passage) with two opposite surfaces roughened by 45 deg parallel ribs. Copper plates fitted with a silicone heater and instrumented with thermocouples are used to measure regionally averaged local heat transfer coefficients. Reynolds numbers studied in the channel range from 30,000 to 400,000. The rib height to hydraulic diameter ratio ranges from 0.1 to 0.18. The rib spacing to height ratio ranges from 5 to 10. Results show higher heat transfer coefficients at smaller values of and larger values of , though at the cost of higher friction losses. Results also indicate that the thermal performance of the ribbed channel falls with increasing Reynolds numbers. Correlations predicting Nusselt number (Nu) and friction factor as a function of , , and Re are developed. Also developed are correlations for and (friction and heat transfer roughness functions, respectively) as a function of the roughness Reynolds number , , and .
Heat Transfer and Pressure Drop Correlations for Square Channels With 45 Deg Ribs at High Reynolds Numbers
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Rallabandi, A. P., Yang, H., and Han, J. (May 14, 2009). "Heat Transfer and Pressure Drop Correlations for Square Channels With 45 Deg Ribs at High Reynolds Numbers." ASME. J. Heat Transfer. July 2009; 131(7): 071703. https://doi.org/10.1115/1.3090818
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