Heat transfer is the process of thermal energy moving from a higher temperature object to a lower temperature one. It's crucial in chemical engineering for designing and optimizing processes such as heating, cooling, and temperature control in reactors and heat exchangers.
The three modes of heat transfer are conduction (heat transfer through a solid or stationary fluid), convection (heat transfer through a moving fluid), and radiation (heat transfer through electromagnetic waves).
Thermal conductivity is a material property that indicates the ability of a material to conduct heat. High thermal conductivity means the material can transfer heat efficiently, which is important for designing heat exchangers and insulation materials.
The heat transfer coefficient is a measure of the convective heat transfer between a surface and a fluid. It is significant because it helps determine the rate of heat transfer in convective processes, influencing the design of heat exchangers and cooling systems.
Steady-state heat transfer occurs when the temperature profile does not change over time, whereas transient heat transfer occurs when the temperature profile changes over time until a new steady state is reached.
A heat exchanger is a device designed to efficiently transfer heat between two or more fluids. It is used in various chemical processes to heat or cool fluids, recover heat, and improve energy efficiency.
The overall heat transfer coefficient combines the effects of conduction, convection, and any fouling on both sides of a heat exchanger. It is crucial for determining the efficiency of heat exchangers and for their design and analysis.
Factors affecting convective heat transfer include fluid velocity, fluid properties (such as viscosity and thermal conductivity), surface area, temperature difference between the fluid and the surface, and the nature of the fluid flow (laminar or turbulent).