Principles of Heat Transfer

Summary:

“Heat Transfer” is a study that discusses the rate of energy transfer between places in non-equilibrium states, and is applied in determining the heat transfer rate and system size for heat transfer at a specified rate. Heat transfer relies on thermal, voltage, or pressure differences. The rate of heat transfer is dependent on the temperature gradient. There are several aspects to consider about internal energy, including Sensible Energy, Latent Energy, Chemical Energy, and Nuclear Energy.

Heat transfer occurs through Conduction, Convection, and Radiation. Conduction transfers energy from more energetic particles to less energetic particles due to vibrations in solids and collisions in fluids. Convection is energy transfer between a solid surface and an adjacent liquid or gas and can be Free Convection or Forced Convection. Radiation is energy emitted by matter through electromagnetic waves or photons.

Several key laws and principles are discussed, such as Fourier’s Equation, Newton’s Law of Cooling, Stefan-Boltzmann Law, Planck’s Law, and Kirchhoff’s Law. Additionally, thermal diffusivity, convection numbers, emissivity, incident radiation, and heat exchanger temperature differences are important components in understanding heat transfer.

Excerpt:

Principles of Heat Transfer

What is Heat Transfer
It discusses the rate of energy transfer from one place to another in a non-equilibrium state while Thermodynamics discusses the amount of energy from one equilibrium phase to another equilibrium phase. Heat Flow exists because of Thermal Difference, Electricity Flow exists because of Voltage Difference, and Fluid Flow exists because of Pressure Difference.

It is commonly practised and applied to determine the heat transfer rate flowing in or out and the system size for heat transfer at a specified rate.

The rate of Heat Transfer depends on the Temperature Gradient, which is expressed as temperature gradient with respect to length.

dT/dx

The method of Heat Transfer and other flow-related phenomena depends on the difference where the energy/fluid travels from a higher state to a lower state. An example of this principle is the Zeroth Law of Thermodynamics.