Modeling & Simulation of a Cooling Tower with COMSOL Multiphysics

Abstract: The aim of this project is to create a model of a Cooling Tower setup using COMSOL Multiphysics. Experiments are performed on the setup in order to provide data of the behaviour. The model is fitted to the data by estimate the models parameters. The parameter estimation is performed with MATLAB by connecting the programs using LiveLink, COMSOL 5.0 with MATLAB. The heat transport coefficient,h_g, is estimated from Onda´s method but to be able to adjust the coefficient it is multiplied with the term,n_hg.The term,n_hg, is estimated to 30.6 and this results in that heat transport coefficient varies between 14.5-15.7 kW/m2°C. The model assumes that interface temperature is the wet bulb temperature. In reality is this temperature higher increases the humidity at the interface creating a greater gradient and therefore a bigger driving force. An increased driving force means that the heat transfer coefficient decrease. By adjusting the interface temperature the mass transfer coefficient can have a more correct value. The simulation shows that the model has a more aggressive heat removal at lower liquid flow rates compared to the data. This could be a result of uneven distribution in the experiments while the model assumes prefect distribution.