Heat transfer and friction factor correlations for a solar air heater duct roughened artificially with V-ribs with symmetrical gaps

CFD Analysis on the Thermal Hydraulic Performance of an SAH Duct with Multi V-Shape Roughened Ribs

“…For shape optimization the explanation domain used for the CFD simulation is shown in Figure 13. Roughness parameters were selected such as Gd{Lv = 0.69 W{w = 6.0, P{e = 8.0, e{D = 0.043, α = 60˝, S R {e = 2.5, Ps{P = 0.6 and e{d = 0.5 based on the optimal values of these parameters stated in the literature [1,2,[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Relative discrete width pg{eq is selected as 1.0 based on optimal value of this parameter in current CFD study.…”

“…It was suggested that inclination of the ribs resulted in the generation of secondary flow by the movement of counter-rotating vortices between two consecutive parallel ribs [6], which swept the floor between two ribs, resulting in the increase of heat transfer from the leading end region, whereas a trailing end region produced lower heat transfer coefficients due to accumulation of hot fluid. V-shaped ribs were believed to improve the span-wise distribution of heat transfer by doubling the counter-rotating secondary flow regions [11][12][13][14][15]. Multi V-shaped ribs further improved the thermal performance due to the increase in the density of counter-rotating secondary flow vortices [16].…”

“…Other investigations explored the effect of continuous ribs in various arrangements such as: angled rib [6], V-rib [9,10], discrete V-rib [11][12][13][14][15], multi V-rib [16] and arc-shaped rib [17]. Use of inclined ribs resulted in the improvement of heat transfer as compared to the transverse ribs.…”

“…A further enhancement of the heat transfer can be expected when using a multi V-shaped rib, as this design increases the number of secondary flow cells by several times, compared to a single V-shaped rib spreading over the entire width of the absorber plate [15]. Even though previous studies have shown that multiple V-shaped ribs on the absorber plate could increase the average Nusselt number of a SAH, the heat transfer enhancement mechanism needs to be demonstrated more clearly, especially the effect of the secondary flow behaviors on the heat transfer enhancement [16].…”

Laminar Forced Convection and Heat Transfer Characteristics in a Square Channel Equipped with V-Wavy Surface

“…The V-rib/baffle (Abraham and Vedula, 2016;Deo et al, 2016;Fang et al, 2015;Jin et al, 2017;Kumar and Kim, 2016;Maithani and Saini, 2016;Promthaisong et al, 2016;Ravi and Saini, 2016;Singh and Ekkad, 2017) is another type of the vortex generators, which always use to increase heat transfer rate and thermal performance in tube/channel heat exchanger. The V-rib gives high heat transfer rate and thermal performance, but also performs enlarge pressure loss.…”