An electrical machine dissipates 2.5 kW. All cooling of the unittakes place through one exposed surface, measuring 120 mm × 190 mm.All other surfaces of the unit are insulated. 50 fins are mountedon the exposed surface. The fins are made of aluminium alloy2024-T6, and each one measures 120 mm × 2 mm in cross-section and80 mm in length (normal to the surface they are mounted on). Thefins and base surface are exposed to fan-driven air at 15°C with aconvection heat transfer coefficient of 60 W m–2 K–1. Calculate thesteady-state temperature of the power supply’s exposed surface. (b)To increase the heat transfer rate through a set of fins, withoutchanging the base temperature, would it be more effective toincrease the number of fins by 20%, or to increase the length ofeach fin by 20%? Explain your answer.
