Question

What is the concept of overall coefficient of heat transfer is used in heat transfer problems?

(a) Conduction

(b) Convection

(c) Radiation

(d) Conduction and convection

I got this question in an interview for job.

I would like to ask this question from Internal Mass Transfer and Reaction in portion Heterogenous Reactions of Bioprocess Engineering

Answer 1

The overall coefficient of heat transfer is typically used in heat transfer problems to account for all modes of heat transfer involved in a system. In most practical situations, heat transfer occurs via multiple mechanisms, such as conduction, convection, and radiation. The overall heat transfer coefficient combines the effects of these mechanisms.

However, for the context of heat transfer in a bioprocess—especially in systems like reactors where heat transfer is important—the overall coefficient is most often related to conduction and convection because these are the primary modes of heat transfer in most biological systems.

Answer:

The correct answer is (d) Conduction and convection.

This is because the overall coefficient of heat transfer in many processes (including bioreactor systems) primarily involves conduction (through solid materials) and convection (to and from the fluid surrounding the solid materials), with radiation being less significant in most bioprocess engineering scenarios.