Thermal hydraulic characteristics of turbulent single-phase flow in an enhanced tube using louvered strip insert with various slant angles

Computational Fluid Dynamics Analysis of an Enhanced Tube with Backward Louvered Strip Insert

“…Re, and therefore also the convective heat transfer, improved accordingly. These results are in coherence with previously conducted studies [13][14][15]. Figure 5 also shows that, for backward louvered strip inserts, a pitch S of 40 mm provided the highest Nu and was followed by those of 50 and 60 mm.…”

“…Moreover, as represented in Figures 5 and 10, the present calculation provides the correlation of the Nu and f to Re, respectively. The tendency is considered consistent with the experimental results from previous works [13][14][15]. It is reasonable that the backward louvered strip inserts can give a higher friction factor compared to the forward design [14] because the fluid flow is directly blocked by the louvered strip inserts with the backward arrangement.…”

“…The Nu values for the backward louvered insert with the corresponding pitches of 40, 50, and 60 were in a similar range along the increased Re. Compared to the forward louvered inserts [14], the present tube designs provided a significant improvement of heat transfer. In order to verify the heat transfer enhancement influenced by the presence of a backward louvered insert, a comparison with the plain tube (without insertion) was conducted, which is also shown in Figure 5.…”

“…Hence, it can be concluded that the backward louvered insert increases the friction factor significantly in comparison to the plain tube, which is attributed to the blockage and subsequent diminishment of the flow momentum generated by the backward louvered tape as well as the pressure drop for the corresponding backward louvered tape tube design. higher friction factor compared to the forward design [14] because the fluid flow is directly blocked by the louvered strip inserts with the backward arrangement.…”

“…Most published reports on heat transfer augmentation by louvered strip inserts are experimental studies, which are lacking the evidence to describe the mechanism of both fluid flow and heat transfer. Hence, after studying and publishing the research works in [13,14], we were strongly motivated to continue the work to a numerical analysis of the thermal hydraulic performance inside an enhanced tube equipped with a louvered strip insert with various pitches for turbulent single-phase flow. This is the reason that this work is believed to be able to give a novel academic contribution, especially when compared with the currently available and previously published studies.…”