Search results
Results From The WOW.Com Content Network
Heat of combustion. The heating value (or energy value or calorific value) of a substance, usually a fuel or food (see food energy ), is the amount of heat released during the combustion of a specified amount of it. The calorific value is the total energy released as heat when a substance undergoes complete combustion with oxygen under standard ...
The specific heat of the human body calculated from the measured values of individual tissues is 2.98 kJ · kg−1 · °C−1. This is 17% lower than the earlier wider used one based on non measured values of 3.47 kJ · kg−1· °C−1. The contribution of the muscle to the specific heat of the body is approximately 47%, and the contribution ...
In thermodynamics, the specific heat capacity (symbol c) of a substance is the amount of heat that must be added to one unit of mass of the substance in order to cause an increase of one unit in temperature. It is also referred to as massic heat capacity or as the specific heat. More formally it is the heat capacity of a sample of the substance ...
Thermal diffusivity. In heat transfer analysis, thermal diffusivity is the thermal conductivity divided by density and specific heat capacity at constant pressure. [1] It is a measure of the rate of heat transfer inside a material. It has units of m 2 /s. Thermal diffusivity is usually denoted by lowercase alpha ( α ), but a, h, κ ( kappa ...
through a surface. In physics and engineering, heat flux or thermal flux, sometimes also referred to as heat flux density [1], heat-flow density or heat-flow rate intensity, is a flow of energy per unit area per unit time. Its SI units are watts per square metre (W/m 2 ). It has both a direction and a magnitude, and so it is a vector quantity.
Heat capacity or thermal capacity is a physical property of matter, defined as the amount of heat to be supplied to an object to produce a unit change in its temperature. [1] The SI unit of heat capacity is joule per kelvin (J/K). Heat capacity is an extensive property. The corresponding intensive property is the specific heat capacity, found ...
The value obtained this way is said to be the molar heat capacity at constant volume (or isochoric) and denoted c V,m, c v,m, c v,m, etc. The value of c V,m is always less than the value of c P,m. This difference is particularly notable in gases where values under constant pressure are typically 30% to 66.7% greater than those at constant volume.
A hot fluid's heat capacity rate can be much greater than, equal to, or much less than the heat capacity rate of the same fluid when cold. In practice, it is most important in specifying heat-exchanger systems, wherein one fluid usually of dissimilar nature is used to cool another fluid such as the hot gases or steam cooled in a power plant by a heat sink from a water source—a case of ...