UNIVERSIDAD DE COLIMA ****
ALUMNO: MICHAEL ANOTNIO GAYTAN MEDINA 7A**** PROFESOR: GUZMAN VEGA HECTOR GUSTAVO
Conduction shape factor
NOUN
Heat flow between two surfaces, any other surfaces being adiabatic.
Example: The heat transfer from one surface (at a temperature T1) to the other surface (at T2) can be expressed as: q=Sk(T1-T2) where k is the thermal conductivity of the solid and S is the conduction shape factor.
en: Factor de forma de conducción
Convection resistance
noun
In order to calculate the convective resistance the heat transfer coefficient, h must first be determined. Many correlations exist to calculate the heat transfer coefficient depending on of the geometry of the system being considered.
Example: e SI unit of absolute thermal resistance is kelvins per watt (K/W) or the equivalent degrees Celsius per watt (°C/W) – the two are the same since the intervals are equal: ΔT = 1 K = 1 °C.
en: Resistencia a la convección
Critical radius of insulation
NOUN
Is a counterintuitive concept within the study of heat transfer. The theory states that adding insulation to a cylindrical or spherical object will increase the rate of heat loss rather than decrease it, if the radius (thickness) of the insulation is at its “critical” value.
Example: In the case of cylinders and spheres it is called critical radius. It can be derived the critical radius of insulation depends on the thermal conductivity of the insulation k and the external convection heat transfer coefficient h.
en: Radio crítico de aislamiento
Cylinder conduction resistance
NOUN
Is a elementary thermal resistance relation canbe expressed as follows. Its a heat property and a measurement of a temperature difference by which an cylinder resists a heat flow.
Example: Consider steady heat conduction through a hot-water pipe. Heat is continuously lost to
the outdoors through the wall of the pipe, and we intuitively feel that heat transfer
through the pipe is in the normal direction...
en: Resistencia de conducción del cilindro
Efficiency
noun
is the ability to avoid wasting materials, energy, efforts, money, and time in doing something or in producing a desired result. In a more general sense, it is the ability to do things well, successfully, and without waste.
Example: A common but confusing way of distinguishing between efficiency and effectiveness is the saying "Efficiency is doing things right, while effectiveness is doing the right things
en: Eficiencia
Fin effectiveness
noun
It is defined as the ratio of the actual heat transfer that takes place from the fin to the heat that would be dissipated from the same surface area without fin.
is defined as the ratio of actual heat flow of the fin to that which would be obtained with a fin of constant temperature uniformly equal to the base surface temperature, that is, one with infinite thermal conductivity.
Example: Then, if the efficiency of a fin is known, the heat transferred by the fin can readily be determined.
Interface resistance
NOUN
is a measure of an interface's resistance to thermal flow. This thermal resistance differs from contact resistance (not to be confused with electrical contact resistance) because it exists even at atomically perfect interfaces.
Example: Molecular dynamics (MD) simulations are a powerful tool to investigate interfacial thermal resistance. Recent MD studies have demonstrated that the solid-liquid interfacial thermal resistance is reduced on nanostructured solid surfaces by enhancing the solid-liquid interaction energy per unit area, and reducing the difference in vibrational density of states between solid and liquid.
en: Resistencia de interfaz
Plane wall conduction resistance
NOUN
Let us consider a plane homogenous wall of thickness with a constant having thermal conductivity.
Let us suppose constant temperature t1 & t2 are maintained on the surface of walls and temperature varies only in the direction of the x-axis which is perpendicular to the wall, therefore the temperature field is one dimensional and the flat isothermal surfaces are arranged perpendicular to the x-axis.
Example: Consider steady heat conduction through the walls of a house during a winter day. We
know that heat is continuously lost to the outdoors through the wall.
en: Resistencia a la conducción de la pared plana
Radiation resistance
NOUN
The radiation resistance can be defined as the value of resistance that would dissipate the same amount of power as radiated as radio waves by the antenna with the antenna input current passing through it.
Example: In a receiving antenna the radiation resistance represents the source resistance of the antenna, and the portion of the received radio power consumed by the radiation resistance represents radio waves reradiated (scattered) by the antenna.
en: Resistencia a la radiación
Sphere conduction resistance
Is a elementary thermal resistance relation canbe expressed as follows. Its a heat property and a measurement of a temperature difference by which an sphere resists a heat flow.
Example: Consider heat conduction through a hollow sphere of inner radius r1, outer radius r2 and made of a material of constant thermal conductivity. The inner and outer surfaces are maintained at constant but different temperatures t1 and t2 respectively.
en: Resistencia a la conducción de la esfera
Surfaces
noun
is the outermost or uppermost layer of a physical object or space.
Example: The property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of its molecules.
en: SUPERFICIE
Thermal contact conductance
NOUN
is the study of heat conduction between solid bodies in thermal contact. The thermal contact conductance coefficient,, is a property indicating the thermal conductivity, or ability to conduct heat, between two bodies in contact. The inverse of this property is termed thermal contact resistance.
Example: Thermal contact resistance is significant and may dominate for good heat conductors such as metals but can be neglected for poor heat conductors such as insulators.
en: Conductancia de contacto térmico
Thermal contact resistance
noun
is defined as the ratio between this temperature drop and the average heat flow across the interface.
Example: In order to minimize the impact of thermal contact resistance, a flexible material with a high thermal conductivity is added to the specimen, hot plate, and cold plate.
en: Resistencia al contacto térmico
Total thermal resistance
NOUN
Is a heat property and a measurement of a temperature difference by which an object or material resists a heat flow.
Example: The total resistance of an element includes all of the resistances of the individual materials that make it up as well as both the internal and external air-film resistance. Its units are the inverse of conductivity.
