Experimental Investigation of Thermohydraulic Performance of the Solar Air Heater Having Arc-Shaped Ribs With Multiple Gaps

Abstract

In the present research, the thermohydraulic performance of a solar air heater having artificial roughness in the form of arc-shaped ribs with multiple gaps has been investigated experimentally and compared with that of a solar air heater having smooth absorber plate. The performance has been investigated in terms of enhancement in the Nusselt number and friction factor. Results of the present work have also been compared with previously published work. Reynolds number and arc angle (α) were varied from 3000 to 18,000 and 30 deg to 75 deg, respectively. Present roughness results in a higher rate of heat transfer from the absorber surface to air, but it also imposes a penalty in terms of the increased friction factor. Maximum enhancement in Nusselt number, friction factor, and thermohydraulic performance parameter for the roughened absorber surface is found to be 3.74, 2.69, and 2.75 times that of the smooth plate, respectively. Correlations of heat transfer and friction factor for proposed roughness have also been developed.

Thermal performance of solar air heater having discrete symmetrical arc rib with staggered rib roughness

“…Figure 12 manifests that Nu of present study is better than roughness geometries of Jain et al 32 and Ambade and Lanjewar 33 due to presence of additional gap that helps in both flow acceleration and breakdowns of formation of peripheral boundary layer alongside of ribs. Figure 12 shows higher f in complete range of Re taken into account for present study than exiting geometry of Jain et al 32 and Ambade and Lanjewar. 33 THPP is used established collective consequence of Nu and f. The THPP variation in Figure 13 corresponds to the range of Re that has been studied.…”

“…Outcomes of experimental investigations of discrete symmetrical arc rib with staggered rib geometry and available best arc rib geometries as listed in Table 2 were compared under similar operating conditions. The roughness geometries of Jain et al 32 and Ambade and Lanjewar 33 were refabricated independently on the absorber plate with optimal parameters declared in literature to maintain the similar flow pattern. Similar environmental operating conditions were provided for roughness geometries of 32,33 and for present study.…”

“…The roughness geometries of Jain et al 32 and Ambade and Lanjewar 33 were refabricated independently on the absorber plate with optimal parameters declared in literature to maintain the similar flow pattern. Similar environmental operating conditions were provided for roughness geometries of 32,33 and for present study. Figure 11 shows the photographic view of geometries prepared for comparison and Table 2 shows the range of operating parameters.…”

A detailed review on research, technology, configurations and application of wire ribs as artificial roughness in rectangular solar air heater duct

“…Arc shape with symmetrical multiple gaps. Jain et al [61][62][63] have proposed investigation for multiple gaps in single arc shape roughness geometry as shown in supplementary Fig. 19.…”

Experimental analysis and thermal management of solar air heater roughened with sine wave baffles

“…The poor heat carrying capacity of air due to the lower value of the convective coefficient deteriorates the performance of SAHs. 5 In wide-open literature, various techniques such as providing artificial roughness in form of ribs, 6,7 fins, 8,9 baffles, 10,11 winglets 12,13 on the heat-absorbing surface of conventional flat plate SAHs, impingement jets, 14,15 etc. have been implemented to improve performance of SAHs by breaking the viscous layer that is accumulated over the heat-absorbing surface.…”