Path: Thermal/ThermalAnalysis
% Creates a set of first order differential equations to model a thermal circuit. Inputs are the nodal masses, a conductive node map, a radiative node map, an input node map and an output node map. The output is a set of first order differential equations in the form . T = aT + bq y = cT where T is the nodal temperature, q is the thermal input and y is the vector of measurements. A node map has one row for each node and as many columns as are necessary to specify the connections. Each node map is accompanied by a coefficient map that gives either the conductive or radiative heat transfer coefficents for the node pair. Radiative heat transfer is of the form: 4 4 q = a(T - T ) ij i j Thermnet linearizes about the nominal temperature. The result is 3 3 q = a(T T - T T ) ij ni i nj j where the n indicates a nominal temperature. The radiative heat transfer coefficient causes an asymmetry between nodes. Thermnet will automatically make the a matrix symmetric for conduction. Thermnet will warn you if you entered a coefficient twice and the two were different. You only have to specify the connection in one direction. If you want a node to conduct or radiate to infinity just input "inf" as the node to which it is radiating or conducting. Since version 1. -------------------------------------------------------------------------- Form: [a, b, c, ac, ar] = Thermnet( mn, cnm, cc, inm, onm, rnm, rc, tnom ) -------------------------------------------------------------------------- ------ Inputs ------ mn (1,n) Thermal mass of each node cnm (n,:) Conduction node map cc (n,:) Conduction coefficients inm (m,:) Input node map (nodes with inputs) onm (p,1) Output node map (nodes with outputs) rnm (n,:) Radiation node map rc (n,:) Radiation coefficients tnom (1,n) Nominal temperature for linearization ------- Outputs ------- a (n,n) Plant matrix b (n,m) Input matrix c (p,n) Output matrix ac (n,n) Conduction part of the plant matrix ar (n,n) Radiative (quartic) coefficient matrix --------------------------------------------------------------------------
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