The purpose of this glossary is that the new concepts that we are learning throughout the subject are as clear as possible.
Conduction shape factor
Noun
S is the conduction shape factor, which has the dimension of length, and k is the thermal conductivity of the medium between the surfaces. The conduction shape factor depends on the geometry of the system only.
Example: Form factor in conduction, S, is related to the thermal resistance R by R = 1 / kS or S = 1 / kR. Therefore, these two quantities are the inverse of each other when the thermal conductivity of the medium is unity.
en: Factor de forma en la conducción
Convection resistance
Noun
Is the thermal resistance of the surface against heat convection or simply the resistance to convection of the surface.
Example: When the convection heat transfer coefficient is very large, the convection resistance becomes zero. That is, the surface does not offer resistance to convection and therefore does not slow down the heat transfer process. It tends to this situation in the practice on surfaces where boiling and condensation occur.
en: Resistencia a la convección
Critical radius of insulation
Noun
By drifting and clearing r2 it follows that the critical insulation radius for a cylindrical body.
Example: The critical radius of insulation depends on the thermal conductivity of the insulation k, and of the external heat transfer coefficient h by convection, h.
en: Radio crítico de aislamiento
Cylinder conduction resistance
Noun
The thermal resistance of the cylindrical layer against heat conduction or, simply, the conduction resistance of the cylindrical layer.
Example: It is expressed as shown in the figure.
en: Resistencia de conducción del cilindro
Efficiency
Noun
It is a dimensionless performance measure of a device that uses thermal energy.
Example: For a heat engine, thermal efficiency is the fraction of the energy added by heat (primary energy) that is converted into net work output (secondary energy).
en: Eficiencia
Fin effectiveness
Noun
Fins are used to improve heat transfer and cannot be recommended for use unless improved transfer justifies the additional cost and the complexity associated with them.
Example: The performance of the fins is judged on the basis of the improvement in heat transfer compared to the case in which they are not used. fins.
en: Eficiencia de las aletas
Fin efficiency
Noun
An efficiency of the fin is defined as: (Actual ratio of heat transfer from the fin / Ideal ratio of heat transfer from the fin if it was all at the base temperature).
Example: It is expressed as shown in the figure.
en: Eficiencia de las aletas.
Interface resistance
Noun
Boundary conditions at an interface are based on the requirements of that 1) the two bodies in contact must have the same temperature in the contact area and 2) an interface (which is a surface) cannot store energy and therefore the heat flux on both sides of the interface must be yourself.
Example: It is expressed as shown in the figure.
en: Resistencia de interfaz
Plane wall conduction resistance
Noun
The thermal resistance of the wall against heat conduction or simply the conduction resistance of the wall. Note that the resistance temperature of a medium depends on the geometric configuration and the thermal properties of the medium.
Example: The conduction resistance of each wall is L / kA connected in series and applying the electrical analogy. That is, by dividing the difference in temperature that exists between the two surfaces at known temperatures between the total thermal resistance that both present. Consider a flat wall consisting of two layers (like a brick wall with one layer of insulation).
en: Resistencia a la conducción de la pared plana.
Radiation resistance
Noun
The thermal resistance of a surface against radiation, or the resistance to radiation.
Example: It is expressed as shown in the figure.
en: Resistencia a la radiación
Sphere conduction resistance
Noun
The thermal resistance of the spherical layer against heat conduction or, simply, the resistance to conduction of the spherical layer.
Example: It is expressed as shown in the figure.
en: Resistencia a la conducción de la esfera
Surfaces
Noun
The outer or top part or layer of something.
Example: On an isolated surface, the first derivative of the temperature with respect to the spatial variable (the temperature gradient) in the direction normal to that isolated surface is zero.
en: Superficies
Thermal contact conductance
Noun
The quantity (hc), which corresponds to the convection heat transfer coefficient, is called the contact thermal conductance.
Example: It is expressed as shown in the figure.
en: resistencia térmica por contacto
Thermal contact resistance
Noun
An interface offers some resistance to heat transfer, and this resistance per unit area of the interface is called contact thermal resistance.
Example: It is expressed as shown in the figure.
en: Resistencia térmica por contacto.
Total thermal resistance
Noun
The total thermal resistance is simply the arithmetic sum of each of the thermal resistances that is are in the path of heat transfer.
Example: The total thermal resistance of a structure can be determined with the greatest accuracy in a lab, by actually assembling the unit and testing.
