Radiative Exchange in Heat Transfer: View Factors and Properties

This lecture covers the principles of radiative exchange between surfaces, focusing on view factors for various surface types. The instructor begins by introducing the concept of view factors, emphasizing their geometric nature and the assumptions of homogeneous and isotropic intensity from surfaces. Key properties such as reciprocity, summation, and additive properties of view factors are discussed, illustrating their importance in energy conservation and calculations. The lecture progresses to the derivation of equations for radiative exchange, starting with black surfaces and extending to gray and diffuse surfaces. The instructor explains how to calculate heat flux between surfaces using these equations, highlighting the role of emissivity and the impact of surface geometry. Practical examples, including infinite parallel plates and concentric cylinders, are provided to demonstrate the application of these concepts. The lecture concludes with a discussion on radiation shields and their effect on radiative heat transfer, reinforcing the theoretical principles with real-world applications.