ANSYS Fluent simulation of a solar chimney

Abstract

This final degree project aims to model a chimney to incorporate it in a future work, which is a whole solar chimney model, also to compare temperature data obtained from an experimental pilot plant (literature) with temperature data obtained from two ANSYS® simulated models. To make a comparison of the results, there will be a study of temperature at different heights marked as 10#, 11# and 12#, matching the available experimental points. The simulation used models are: model with atmosphere, to obtain the indoor and outdoor data as accurate as possible, and a model without atmosphere. Once the results are obtained and compared to experimental data, the both simulated models would be compared between them. Finally, there will be studies of temperature, density, velocity and turbulence for both. There is detailed explanation of each ANSYS® module. The explained modules are the Geometry design, Mesh Generation and Model Setup of Fluent, being this last one to quantify and export results, emphasizing in distributions, profiles, contours and values of temperature, density and velocity throughout the system. In the Geometry Design, the chosen geometry was 2D, in order to make it easier to compute. The solar chimney dimensions are: a cylinder with, 8 m high and 30 cm diameter for both models. In the atmosphere model, the atmosphere dimensions surrounding chimney cylinder are 160 meters high and 3 meters in width with respect to the center of the chimney. For both models, the outdoor temperature and pressure are 305.5 K and 101,325 Pa respectively. The chimney inlet temperature is 322.4 K. The pictures were obtained as contour and vector formats. The distributions of temperature, density, velocity and turbulence throughout the system are shown. The graphical profiles of temperature, density and speed at different heights and, the numerical data tables of temperature, density, velocity and Reynolds, are shown for both models too. The obtained results of the simulation, have a similarity for the atmosphere model and the model without atmosphere of 99.7% and 99.5% respectively between them and the experimental data. The results of temperature in each of the predetermined heights are nearly identical to the experimental data in both simulations. The atmosphere model reproduces more realistic results than the model without atmosphere. Given that the goal of the study is to compare the results with a real case, confirms the fact that the two models give acceptable and similar values. If there is an interest in designing a new chimney, it is recommended the implementation of the atmosphere model. Given the results of comparing models, it is verified that all the results as density, speed, Reynolds and heat transfer coefficients are correct.