Design, Modelling and Optimizing Heat Pipe Radiating Fins for Spacecraft/Satellite Cooling

Abstract

Different heat pipe fin geometries were designed, modelled, and optimized to study the effect of various fin shapes on the heat transfer in no gravity environment for a 6U CubeSat application. The advantage of using heat pipe radiating fins include the significant improvement in heat transfer with respect to mass and size.

Different solid fins geometries were modelled using ANSYS Steady State Thermal. In addition, different optimization parameters were set for the various geometries, such as, fin thickness 𝑡, fin width 𝑊, number of fins 𝑛, fin diameter 𝐷𝑓, and fin height 𝐻. A condenser of length 𝐿 = 120 𝑚𝑚, outer diameter 𝑂𝐷 = 6 𝑚𝑚, and inner diameter 𝐼𝐷 = 4mm, was used as the base model. Moreover, different operating temperatures were considered in this study, varying from 𝑇 =50℃−80℃. This was done to determine the most optimum fin geometry at different operating conditions. The net outgoing radiated heat per unit mass was used to verify the optimum fin geometry.

In general, this optimization study suggests triangular longitudinal fins of count 𝑛 = 2, base thickness 𝑡𝑏 = 0.5 𝑚𝑚, and fin width 𝑊 = 30 𝑚𝑚. In addition, the parametric study concluded that rectangular cross-sectional fins and circular annular fins do not improve the condenser/fin system net outgoing radiated heat per unit mass. On the other hand, as fin width increases for rectangular longitudinal fins, trapezoidal longitudinal fins, and triangular longitudinal fins the net outgoing radiated heat per unit mass increases; however, the increase becomes insignificant after exceeding 𝑊 = 30 𝑚𝑚. In addition, exceeding 𝑊 = 60 𝑚𝑚 results in a decrease in net outgoing radiated heat per unit mass. Also, decreasing fin thickness results in higher values of net outgoing radiated heat per unit mass. According to the optimization study, increasing the number of fins beyond 𝑛 = 3 reduces the heat transfer rate per unit mass.

Also, this study considers the effect of changing the condenser/fin system material on the net outgoing radiated heat per unit mass. Aluminum, copper, and carbon-composite were the materials of study. Carbon-composite provided the highest results because it is the lightest in weight and has the highest emissivity.

Furthermore, the effect of increasing the operating temperature on the net outgoing radiated heat per unit mass was conducted. It was concluded that increasing the operating temperature increases the amount of radiated heat per unit mass of the condenser/fin system.

Date of Award	Dec 2022
Original language	American English
Supervisor	MD FAZLULKARIM (Supervisor)