Table of Contents
When lumped system analysis is used?
The lumped system analysis is the method used for the analysis of transient heat transfer systems. The method is used when there is no temperature gradient present in the object to be analyzed for the complete heat transfer process. It means that the temperature of the body should be uniform throughout the object.
What is lumped parameter analysis?
A lumped-capacitance model, also called lumped system analysis, reduces a thermal system to a number of discrete “lumps” and assumes that the temperature difference inside each lump is negligible. This approximation is useful to simplify otherwise complex differential heat equations.
What is meant by lumped system?
A lumped system is one in which the dependent variables of interest are a function of time alone. In general, this will mean solving a set of ordinary differential equations (ODEs) A distributed system is one in which all dependent variables are functions of time and one or more spatial variables.
Which is the true regarding lumped system analysis?
Which is true regarding lumped system analysis? Explanation: Solids have infinite thermal conductivities. It implies that internal conductance resistance is very low. Explanation: The first set in establishing criteria for the applicability of lump system analysis is to define a characteristics length.
What is the difference between lumped and distributed elements?
In lumped elements such as resistors, capacitors, and inductors, physical quantities, such as voltage or current, are functions of time. In distributed elements, the physical quantities associated with the component are distributed in space.
What is the difference between lumped and distributed?
Which material is suitable for lumped analysis?
Therefore, small bodies with high thermal conductivity are good candidates for lumped system analysis. Note that assuming h to be constant and uniform is an approximation. A thermocouple junction, which may be approximated by a sphere, is to be used for temperature measurement in a gas stream.
What is lumped system analysis in heat transfer?
Lumped System Analysis Interior temperatures of some bodies remain essentially uniform at all times during a heat transfer process. The temperature of such bodies are only a function of time, T = T(t). The heat transfer analysis based on this idealization is called lumped system analysis.
What is meant by lumped system analysis?
Temperature of such bodies can be taken to be a function of time only. Heat transfer analysis that utilizes this idealization is known as LUMPED SYSTEM ANALYSIS. If a piece of meat when roasted you will see that the outer parts of roast are well done while the centre part is barely warm.
Is lumped mass analysis an approximation of the amount of heat?
Keep in mind that lumped mass analysis is an approximation because there will be some internal resistance for heat. When we talk about unsteady heat transfer from a body, we need to consider the variation of temperature with spatial coordinates and also with respect to time.
What is Biot number in lumped heat analysis?
To analyze whether a system is applicable to Lumped Heat Analysis , the value of a dimensionless number “Biot Number” is considered. Biot’s number is the ratio of internal resistance ( Conduction) to the external resistance (convection) during heat transfer from a body to surrounding.