High‐flux heat transfer characteristics of pure ethylene glycol in axial and swirl flow

Abstract

AbstractMeasurements were made of heat transfer rates and peak heat flux for atmospheric‐pressure pool boiling, and of adiabatic and diabatic friction factors, nonboiling and local‐boiling heat transfer rates, and burnout heat fluxes for both axial‐ and twisted‐tape swirl‐flow forced convection of pure ethylene glycol. Test sections were electrically heated copper, 347 stainless steel, and A‐nickel tubes.Both axial‐ and swirl‐flow friction factors are in good agreement with available generalized correlations. At the higher Reynolds numbers and heat fluxes axial‐flow nonboiling heat transfer coefficients show a dependence of Nusselt number on NRe0.98 rather than the traditional NRe0.80. Swirl‐flow nonboling heat transfer coefficients from both the glycol data and previously obtained water data are satisfactorily correlated by a single equation. Nucleate‐boiling heat transfer coefficients for both ethylene glycol and water fall approximately 50% above Kutateladze's suggested average line. The atmospheric‐pressure pool‐boiling peak flux is 168,000 Btu/hr. sq. ft. Forced‐convection burnout heat fluxes are correlated in a number of ways, including a new additive method which appears to be generally applicable to a large variety of coolants, geometries, and flow conditions.