A semi-empirical model for free-convection condensation on horizontal pin–fin tubes

Abstract

a b s t r a c tA simple semi-empirical correlation accounting for the combined effect of gravity and surface tension has been developed for condensation on horizontal pin-fin tubes. The model divides the heat transfer surface into five regions, i.e. two types of pin flank, two types of pin root and the pin tip. Data for three fluids (i.e. steam, ethylene glycol and R113) condensing on eleven tubes with different geometries were used in a minimization process to find three empirical constants in the final expression. The model gives good overall agreement (within ±20%) with the experimental data, as well as correctly predicting the dependence of heat-transfer enhancement on the various geometric parameters and fluid types.

Condensation Heat Transfer on Geometrically Enhanced Horizontal Tube: A Review

“…The extent of condensate retention and formation of many sharp surfaces enhancing surface-tension effects on pin-fin tubes are identified to be the important parameters contributing towards the heat-transfer enhancement. The model presented by Ali and Briggs [2] is available to predict heat transfer on the pin-fin tubes reasonably by accounting the effect of both gravity and surface-tension condensate drainage. …”

“…Researchers have successfully identified the optimum geometries, fin shapes, dimensions and materials for integral-fin tubes for a wide range of condensing fluids. A number of theoretical models, for instance Briggs and Rose [1], Ali and Briggs [2], have successfully combined the effect of surface tension and gravity to explain condensation heat transfer on integral-fin and pin-fin tubes. However, relatively fewer investigations have been carried out for condensation on three-dimensionally enhanced tubes.…”

“…Ali and Briggs [2] developed a simple semi-empirical correlation accounting for the combined effect of gravity and surface tension for condensation on horizontal pin-fin tubes. The model divided the heat-transfer surface into five regions, that is, two types of pin flank, two types of pin root and the pin tip ( Figure 7).…”

Improvement and Experimental Investigation of Thermopile Sensor with Dynamic Effects

“…Pin-Fin Tubes [9]. ΔT c = (ΔE-ΔE f ) / 10 * (dT/dE) E=Em (1) (dT/dE) E=Em = 0.0255-0.4580 * 10 -6 * 2Em + 0.2961 * 10 -10 * 3Em 2 + 0.6849 * 10 -14 * 4Em3 -0.6208 * 10 -18 * 5Em 4 (2) Where Em is given as, Em = Ein + (ΔE -ΔEf) / 10/2 (3) ΔE=thermo-emf reading of 10 junction thermopile in μV ΔEf=thermo-emf reading correction for frictional dissipation μV Ein=thermo-emf reading from inlet thermocouple in μV The sensitivity is a function of a parameter, Z, which is expressed as α 2 /(R K).…”

Free convection condensation of steam on horizontal wire wrapped tubes: Effect of wire thermal conductivity, pitch and diameter

“…The best reported enhancement ratio for the case of steam, R-113 and ethylene glycol on pin-fin tubes are 4.1, 9.9 and 5.5 respectively (see Briggs [19], Baiser and Briggs [20] Ali and Briggs [14,15]). Based on the reported experimental data on pin-fin tubes, recently, Ali and Briggs [21] reported a semi-empirical model for condensation heat transfer on pin-fin tubes. Model showed agreement to data within ±20%.…”