Unsteady state condition in heat transfer refers to a situation where temperature distribution within a system changes over time. This means that the system does not reach a steady state where temperatures remain constant. Unsteady state heat transfer occurs during transient processes such as heating up or cooling down a system.
Unsteady state heat transfer occurs when the temperature of an object changes with time, indicating that the system is not in thermal equilibrium. This can happen during the initial warm-up or cool-down of a system, or when there are sudden changes in external conditions affecting heat transfer. The rate of heat transfer during unsteady state conditions is not constant and varies with time.
In steady-state conduction, temperature and heat transfer remain constant with time, while in unsteady conduction, temperature and heat transfer change with time. Steady state occurs when the temperature distribution does not change over time, whereas unsteady state occurs when there is a time-dependent temperature distribution.
In transient heat transfer, the rate of heat transfer is changing with time. By definition, in steady-state heat transfer, the rate of heat transfer does NOT change with time. In the real world, heat transfer starts out as transient and then approaches steady-state with time until the difference between the actual and the ideal becomes negligible or until thermal equilibrium is approached.
An example of a boundary condition in a mathematical model is specifying the temperature at the edges of a heat-conducting material in a heat transfer simulation.
Heat transfer that does not cause a temperature change is called latent heat transfer. This occurs when heat is absorbed or released during a change in state (solid to liquid, liquid to gas) without changing the temperature of the substance.
Unsteady state heat transfer occurs when the temperature of an object changes with time, indicating that the system is not in thermal equilibrium. This can happen during the initial warm-up or cool-down of a system, or when there are sudden changes in external conditions affecting heat transfer. The rate of heat transfer during unsteady state conditions is not constant and varies with time.
In steady-state conduction, temperature and heat transfer remain constant with time, while in unsteady conduction, temperature and heat transfer change with time. Steady state occurs when the temperature distribution does not change over time, whereas unsteady state occurs when there is a time-dependent temperature distribution.
J. E. LaGraff has written: 'Unsteady transonic heat transfer in a transient facility' -- subject(s): Solid surfaces, Rarefied gas dynamics, Gas flow, Aerodynamic heat transfer, Transonic flow, Unsteady flow
heat transfer from one molecule to another
In transient heat transfer, the rate of heat transfer is changing with time. By definition, in steady-state heat transfer, the rate of heat transfer does NOT change with time. In the real world, heat transfer starts out as transient and then approaches steady-state with time until the difference between the actual and the ideal becomes negligible or until thermal equilibrium is approached.
any where but condition is there should be temperature difference
Steady-state heat transfer does not change with time - because - that is the definition of steady-state, i.e. "steady-state" means "does not change with time".As for why heat transfer might be steady state - that would be a consequence of the driving forces and physical conditions remaining constant with time. For example:Heat source remains the same temperatureHeat sink remains the same temperatureHeat source remain in the same position relative to each other, both in terms of distance and orientation.Surface areas of heat source and heat sink remain the same.Any intervening medium remains the same composition, temperature, density, and pressure.If convection is occurring, flow rates remain constant.If radiative heat transfer is occurring, any intervening medium has constant transmissivity, reflectivity, and absorbtion.If radiative heat transfer is occurring, radiating and absorbing surfaces maintain constant radiative and absorbing properties.There are a few other factors that can influence steady-state heat transfer, but these are a good description of the most important ones.
An example of a boundary condition in a mathematical model is specifying the temperature at the edges of a heat-conducting material in a heat transfer simulation.
The study of heat transfer during chemical reactions and changes of state is known as thermochemistry. Thermochemistry deals with the heat of reaction, enthalpy, and heat transfer in chemical processes. It is important in understanding the energy changes associated with chemical reactions.
Rama S. R. Gorla has written: 'Effects of unsteady free stream velocity and free stream turbulence on stagnation point heat transfer' -- subject(s): Transmission, Heat, Fluid mechanics
Heat transfer that does not cause a temperature change is called latent heat transfer. This occurs when heat is absorbed or released during a change in state (solid to liquid, liquid to gas) without changing the temperature of the substance.
Convection is the transfer of heat through the movement of a fluid (liquid or gas). The condition for convection to occur is that the fluid must be in motion, either naturally (natural convection) due to density differences or externally induced (forced convection) by a fan or pump. Heat transfer in convection is more efficient than conduction as it involves both thermal energy transfer and physical movement of the fluid.