Ad
related to: fluid heat transfer calculations
Search results
Results from the WOW.Com Content Network
It is used in calculating the heat transfer, typically by convection or phase transition between a fluid and a solid. The heat transfer coefficient has SI units in watts per square meter per kelvin (W/m 2 K). The overall heat transfer rate for combined modes is usually expressed in terms of an overall conductance or heat transfer coefficient, U ...
The number of transfer units (NTU) method is used to calculate the rate of heat transfer in heat exchangers (especially parallel flow, counter current, and cross-flow exchangers) when there is insufficient information to calculate the log mean temperature difference (LMTD). Alternatively, this method is useful for determining the expected heat ...
Nusselt number. In thermal fluid dynamics, the Nusselt number (Nu, after Wilhelm Nusselt [1]: 336 ) is the ratio of total heat transfer to conductive heat transfer at a boundary in a fluid. Total heat transfer combines conduction and convection. Convection includes both advection (fluid motion) and diffusion (conduction).
A hot, less-dense material at the bottom moves upwards, and likewise, cold material from the top moves downwards. Convection (or convective heat transfer) is the transfer of heat from one place to another due to the movement of fluid. Although often discussed as a distinct method of heat transfer, convective heat transfer involves the combined ...
In fluid dynamics, the general equation of heat transfer is a nonlinear partial differential equation describing specific entropy production in a Newtonian fluid subject to thermal conduction and viscous forces: [1][2] where is the specific entropy, is the fluid's density, is the fluid's temperature, is the material derivative, is the thermal ...
Gravity causes denser parts of the fluid to sink, which is called convection. Lord Rayleigh studied [2] the case of Rayleigh-Bénard convection. [6] When the Rayleigh number, Ra, is below a critical value for a fluid, there is no flow and heat transfer is purely by conduction; when it exceeds that value, heat is transferred by natural ...
Biot number. Ratio of the thermal resistances of a body's interior to its surface. The Biot number (Bi) is a dimensionless quantity used in heat transfer calculations, named for the eighteenth-century French physicist Jean-Baptiste Biot (1774–1862). The Biot number is the ratio of the thermal resistance for conduction inside a body to the ...
Logarithmic mean temperature difference. In thermal engineering, the logarithmic mean temperature difference (LMTD) is used to determine the temperature driving force for heat transfer in flow systems, most notably in heat exchangers. The LMTD is a logarithmic average of the temperature difference between the hot and cold feeds at each end of ...
Ad
related to: fluid heat transfer calculations