Uncertainty analysis of heat-exchanger thermal designs using the Monte Carlo simulation technique

The Monte Carlo simulation technique for determining uncertainties of the thermal parameters needed in designing heat exchangers is discussed. Parameters such as the outside diameter D_o, thickness t and thermal conductivity k are assumed to have Gaussian distributions, while the heat-transfer coefficients h_i, and h_o are considered to follow normal, log-normal and Weibull forms of distribution. An illustrative example is presented. The overall heat-transfer coefficient U obtained from the simulation is found to have a distribution that is well approximated by the Weibull model. Using the Weibull distribution of U, the additional percentage area is calculated for 80 and 99% confidence levels (CLs). The proposed approach of design analysis incorporates realistic risks associated with uncertainties of the parameters.