Enhancement of natural convection heat transfer from a fin by triangular perforation of bases parallel and toward its tip

This study examines the heat transfer enhancement from a horizontal rectangular fin embedded with triangular perforations （their bases parallel and toward the fin tip） under natural convection. The fin＇s heat dissipation rate is compared to that of an equivalent solid one. The parameters considered are geometrical dimensions and thermal properties of the fin and the perforations. The gain in the heat transfer enhancement and the fin weight reduction due to the perforations are considered. The study shows that the heat dissipation from the perforated fin for a certain range of triangular perforation dimensions and spaces between perforations result in improvement in the heat transfer over the equivalent solid fin. The heat transfer enhancement of the perforated fin increases as the fin thermal conductivity and its thickness are increased.

3D numerical study and comparison of thermal-flow performance of various annular finne d-tub e designs

With the increase of heat transfer problems in marine vehicles and submerged power stations in oceans,the search for an efficient finned-tube heat exchanger has become particularly important.The purpose of the present investigation is to analyze and compare the thermal exchange and flow characteristics between five different fin designs,namely:a concentric circular finned-tube(CCFT),an eccentric circular finned-tube(ECFT),a perforated circular finned-tube(PCFT),a serrated circular finned-tube(SCFT),and a star-shaped finned-tube(S-SFT).The fin design and spacing impact on the thermal-flow performance of a heat exchanger was computed at Reynolds numbers varying from 4,300 to 15,000.From the numerical results,and when the fin spacing has been changed from 2 to 7 mm,an enhancement in the Colburn factor and a reduction in the friction factor and fin performances were observed for all cases under study.Three criteria were checked to select the most efficient fin design:the performance evaluation criterion P EC,the global performance criterion G PC,and the mass global performance criterion M G PC.Whatever the value of Reynolds number,the conventional CCFT provided the lowest performance evaluation criterion P EC,while the SCFT gave the highest amount of P EC.The most significant value of G PC was reached with the ECFT;however,G PC remained almost the same for CCFT,PCFT,SCFT,and S-SFT.In terms of the mass global performance criterion,the S-SFT provides the highest M Gpc as compared with the full fins of CCFT(41-73%higher)and ECFT(29-54%higher).Thus,the heat exchanger with S-SFT is recommended to be used in the cooling of offshore energy systems.

Improving shipboard electronics cooling system by optimizing the heat sinks configuration

With the increase of high-power electrical components in modern ships,especially fully electric ships with electric propulsion drive(EPD),the cooling of EPD electrical components has become particularly important.Providing optimal configurations for heat sinks with high thermal efficiency plays an essential role in this regard.A new technique for improving the efficiency of heat sinks is the utilization of perforated fins.This study examined the effects of perforation geometry(shape and size)on laminar airflow flow and heat transfer characteristics over a perforated plate-fin heat sink.Three-dimensional simulations were conducted using the finite-volume scheme based on the SIMPLE algorithm.In this research,the effects of perforation shape and size on various parameters,e.g.,total drag force,average Nusselt number,perforated fin efficiency(PFE),heat transfer performance enhancement(HTPE),and fin optimization factor(η)were evaluated.The results confirmed that at a specific heat transfer surface area for perforated fins,the highest efficiency is achieved by circular perforations.In contrast,the square perforations due to geometric similarity to rectangular fins could reach the maximum size.Consequently,fins with square perforations could achieve the most optimal configuration.Also,results showed that for a constant perforations size,change in perforations shape improves HTPE,PFE,andηby more than 40%,45%,and 110%,respectively.Also,by modifying perforations size for a specified shape,an increment of more than 35%,40%,and 150%is observed in HTPE,PFE,andη,respectively.