Effects of Exterior Surface Dimples on Heat Transfer and Friction Factors for a Cross-Flow Heat Exchanger

Comparative design study of a diesel exhaust gas heat exchanger for truck applications with conventional and state of the art heat transfer enhancements

“…On the other hand, in the present work, sensitivity of the calculated volume of the shell and tube heat exchangers to values chosen for necessary data such as the baffle hole clearances was found negligible as long as TEMA recommendations are adhered to [9]. For finned tubes, Schmidt's method gives a fin efficiency value within 1% of the exact value [9] while for dimpled tubes, the uncertainty in the Nusselt number ratio is ±12.6% [12]. For the metal foam data values, cross-checking with published experimental values gave uncertainties in heat transfer coefficients below 30%.…”

“…Table 3 Parameters used for the Shell and Tube HEX calculations. Table 4 Increment coefficient of heat transfer, used for dimpled tubes [12]. Table 5 Fin characteristics for the plate and fin heat exchanger consisting of plain fins [20].…”

Experimental study of heat transfer and hydraulic resistance at cross flow of tube bundle with indentations

“…Available publications [1][2][3][4][5][6][7][8] consider the cross flow of both a single tube and tube bundles with surface indentations in a wide range of Reynolds numbers. In [1][2][3][4][5], devoted to the cross flow of a single tube, the main emphasis is on the study of hydrodynamic regimes, the point of flow separation, the frequency of vortex shedding, the dependence of the drag resistance on the Reynolds number.…”

“…With the staggered arrangement of tubes, the presence of indentations increases the heat transfer by 20 % and reduces the pressure loss by 35 %. In [8], the results of the experimental study of heat transfer and hydraulic resistance of a four-row tube bundle of staggered arrangement with spherical surface indentations are presented. Deep (h/D=0.37) and shallow (h/D=0.085) spherical indentations were used.…”

“…However, there are contradictions in the results of the works on tube bundles. Thus, in [7], a decrease in hydraulic losses was obtained by using tubes with indentations, and in [6] and [8] -moderate growth. Studies [8] were performed in a very narrow range of Reynolds numbers, which does not allow us to use these results for obtaining reliable dependences.…”