Experimental investigation of heat transfer features for vertical tube using porous media and Carbon dioxide
Bilal Jamal Kkihlefa, Ameer Abed Gaddoa*, Ahmed Hameed Reja
Electromechanical Engineering Department, University of Technology, Iraq-Baghdad
Corresponding Author Email: [email protected]
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
In this work, a vertical tube with porous media and Carbon dioxide have been used in order to study the characteristics of heat transfer at supercritical pressure experimentally. The diameter of tube was 10 mm and the porosity was 0.5. influence of many parameters have been employed such as, mass flow rate, inlet temperature, heat flux to measure the heat transfer characteristics which are; coefficient of heat transfer wall temperature and fluid bulk temperature with taking in consideration the effect of the thermophysical characteristics of super-critical CO2 and buoyancy. The results appeared that the lower pseudocritical temperature (Tpc), than the inlet temperature (To) leads to reduce the coefficient of heat transfer compared with the case of the pseudocritical temperature value higher than the inlet temperatures. Moreover, when the To < Tpc, temperatures of wall a little higher than Tpc and Tpc near the temperatures of fluid bulk, the coefficient of heat transfer reaches to the maximum upward and downward flows along the porous media tube in addition to the heat flux and coefficient of heat transfer are changing nonlinearly. Therefore, these varying in flows for heat transfer coefficient affected on the buoyancy. On the other hand, upward and downward flows working on reduce the coefficient when the temperatures of wall being higher than Tpc.