Experimental Investigation of Transient Heat Transfer in Solid Bodies

Unsteady state (transient) heat transfer plays a critical role in understanding how temperature within a solid body change over time when exposed to a sudden thermal disturbance. Unlike steady-state conduction, where temperatures remain constant with time, transient conduction involves dynamic temperature variations influenced by material properties and environmental conditions. This project investigates the transient cooling behavior of a metallic cylinder using an Unsteady State Heat Transfer Apparatus. The experiment records temperature at regular intervals using embedded thermocouples as the specimen cools from an initial elevated temperature to ambient conditions. Analytical tools such as the lumped capacitance method, Biot number evaluation, and Fourier number assessment are utilized to determine the validity of uniform temperature assumptions. Additionally, the study incorporates advanced transient heat transfer analysis using Heisler charts for systems where internal temperature gradients are significant. A comparison is made between experimental results and theoretical predictions to evaluate the convective heat transfer coefficient and thermal diffusivity of the material. The findings confirm the exponential decay nature of temperature in transient conduction and validate the lumped system model for low Biot number scenarios. This study provides fundamental insight into time-dependent heat transfer processes essential for engineering applications such as thermal management, quenching, material processing, and electronic cooling.