Heat Transfer

(redirected from Heat transfers)

Heat transfer

Heat, a form of kinetic energy, is transferred in three ways: conduction, convection, and radiation. Heat transfer (also called thermal transfer) can occur only if a temperature difference exists, and then only in the direction of decreasing temperature. Beyond this, the mechanisms and laws governing each of these ways are quite different. See Conduction (heat), Convection (heat), Heat radiation

By utilizing a knowledge of the principles governing the three methods of heat transfer and by a proper selection and fabrication of materials, the designer attempts to obtain the required heat flow. This may involve the flow of large amounts of heat to some point in a process or the reduction in flow in others. All three methods operate in processes that are commonplace.

In industry, for example, it is generally desired to extract heat from one fluid stream and add it to another. Devices used for this purpose have passages for each of the two streams separated by a heat-exchange surface in the form of plates or tubes and are known as heat exchangers. The automobile radiator, the hot-water heater, the steam or hot-water radiator in a house, the steam boiler, the condenser and evaporator on the household refrigerator or air conditioner, and even the ordinary cooking utensils in everyday use are all heat exchangers. See Heat

Heat transfer

A generic term for thermal conduction, convection, and radiation.

Heat Transfer

 

the spontaneous irreversible movement of heat in space owing to a nonuniform temperature field. In the general case, heat transfer may also result from the nonuniformity of the fields of other physical quantities; an example is a difference in concentrations. Heat is transferred in three ways: conduction, convection, and radiation. In practice, heat transfer usually occurs through all three mechanisms at the same time.

Heat transfer determines or accompanies many processes in daily life, in technology, and in nature—for example, meteorological processes at the earth’s surface and the evolution of stars and planets. In many cases, such as in the study of dehydration, evaporative cooling, and diffusion, heat transfer is considered together with mass transfer. A special case of heat transfer is the flow of heat from one heat-transfer fluid to another through a solid wall separating the fluids or through an interface between the fluids.

heat transfer

[′hēt ¦tranz·fər]
(thermodynamics)
The movement of heat from one body to another (gas, liquid, solid, or combinations thereof) by means of radiation, convection, or conduction.

Heat transfer

Heat, a form of kinetic energy, is transferred in three ways: conduction, convection, and radiation. Heat transfer (also called thermal transfer) can occur only if a temperature difference exists, and then only in the direction of decreasing temperature. Beyond this, the mechanisms and laws governing each of these ways are quite different. See Conduction (heat), Convection (heat)

By utilizing a knowledge of the principles governing the three methods of heat transfer and by a proper selection and fabrication of materials, the designer attempts to obtain the required heat flow. This may involve the flow of large amounts of heat to some point in a process or the reduction in flow in others. All three methods operate in processes that are commonplace.

In industry, for example, it is generally desired to extract heat from one fluid stream and add it to another. Devices used for this purpose have passages for each of the two streams separated by a heat-exchange surface in the form of plates or tubes and are known as heat exchangers. The automobile radiator, the hot-water heater, the steam or hot-water radiator in a house, the steam boiler, the condenser and evaporator on the household refrigerator or air conditioner, and even the ordinary cooking utensils in everyday use are all heat exchangers. See Heat exchanger

heat transfer

The flow of heat from one body at higher temperature to another body at a lower temperature, until the two temperatures are equal.
References in periodicals archive ?
A detailed analysis of the heat transfer equations used to calculate the total, sensible, and evaporative heat transfers for this experiment can be found in the group's earlier works [4, 5].
In many cases, the finest green beans are roasted by small coffee companies, some of them with limited investment resources that end up choosing hybrid roasters which employ heat transfers by conduction--direct heat under the roasting chamber--and convection because of their relatively lower prices and construction simplicity.
10] analyzed two-dimensional impinging jets and correlated heat transfers in the stagnation point, stagnation region and wall jet region with approximate solutions developed using simplified flow assumptions.
Roll-on and peripheral-decorating equipment used with both foil and preprinted heat transfers.
When they collapse, heat transfers to the liquid without heat transfer surfaces or combustion.
FloWizard can handle fairly simple designs with simple geometries, such as the flow through a duct or a valve, and some kinds of filtration or heat transfers.
Also showing standard and metallic foils as well as heat transfers.
The Acrobot II uses heated rollers or a flat die to apply hot-stamp foils and heat transfers to ovals, squares, triangles, and other shapes across 360[degrees] in a single step.
It can decorate up to 360[degrees] with hot-stamp foils or preprinted heat transfers on parts from 0.
Options include index mechanisms for multicolor heat transfers, rotary tables, fixtures, dies, and parts feeders.
They include units that decorate a wider variety of shapes, including continuous-motion machines for three-dimensional parts and new types of in-mold heat transfers.
Also, heat transfers work well on a variety of thermoplastic substrates - even polypropylene - without pre-treatment.