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ISSN Online: 2379-1748

ISBN Flash Drive: 978-1-56700-469-4

ISBN Online: 978-1-56700-470-0

Second Thermal and Fluids Engineering Conference
April, 2-5, 2017, Las Vegas, NV, USA

TRANSIENT THERMAL CONVEXITY OF TUBULAR HEAT EXCHANGERS

Get access (open in a dialog) pages 683-688
DOI: 10.1615/TFEC2017.cfs.017611

摘要

This paper deals with the transient thermal convexity of tubular heat exchangers. Recently, a fundamental relationship based on the thermal convexity was proposed to describe the thermal behavior of heat exchangers in steady state. This paper treats the extension of this concept to unsteady state thermal behavior of the heat exchangers. The governing equations in transient regime of the thermal convexity coefficients are proposed and a solution with an approximation of a first order response is suggested. The convexity coefficients of both fluids obey to the same transient equations of the temperatures. Analytical expression of the time constants of the thermal convexity coefficients are demonstrated along the tubular heat exchanger when a sudden step change is applied to a mass flow rate of one of the two fluids in co-current and counter current flow arrangements. The thermal convexity times constant of both fluids are similar to those of temperatures compared to experimental measurements obtained from a laboratory pilot-scale heat exchanger [17].