EXPERIMENTAL STUDY OF CONVECTIVE HEAT TRANSFER INSTABILITIES IN TRANSIENT RESPONSE ALONG A COUNTERCURRENT HEAT EXCHANGER

• Published in: Experimental heat transfer Vol. 13; no. 3; pp. 197 - 209
• Main Authors: ABDELGHANI-IDRISSI, M. A, ESTEL, L, BAGUI, F
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA Informa UK Ltd 01.07.2000; Taylor & Francis
• Subjects: Applied sciences; Automatic; Buoyancy-driven instability; Chemical and Process Engineering; Devices using thermal energy; Energy; Energy. Thermal use of fuels; Engineering Sciences; Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); Heat exchangers (included heat transformers, condensers, cooling towers); Hydrodynamic stability; Physics; Reactive fluid environment; Combined convection; Transient response; Fourier transformation; Heat exchanger; Convective instability; Countercurrent flow; Experimental study; Richardson number; Spectral analysis; Temperature fluctuation; Heat transfer; Tubular heat exchanger
• ISSN: 0891-6152; 1521-0480
• DOI: 10.1080/08916150050174887

This article deals with experimental investigations to reveal the effect of combined natural and forced convection in a horizontal tubular countercurrent heat exchanger in both transient and steady states. In transient response, the temperature profiles of hot fluid in a cross section of the inner tube show the influence of buoyancy forces and radial conduction. These profiles are distorted in time and lead to the appearance of oscillating temperature along the inner tube of the heat exchanger. The transient Richardson dimensionless number is calculated to show these effects. Also, a spectral analysis using the discrete Fourier transform has been performed to characterize these temperature instabilities. Using this technique, the influence of flow rates of hot and cold fluids is investigated.