Investigating the increased heat performance of direct steam generation of Fresnel power plant using nanoparticles

摘要

Utilization of direct steam generation is a significant point in the solar power plants particularly in linear Fresnel collectors. In this research, the increased heat transfer coefficient has been scrutinized in the used nanoparticles with volumetric concentrations of 0.01 to 2% in comparison with pure water in the linear Fresnel collectors for two mass fluxes embrace 100 and 500 kg/m~2 s. In this process, determination of critical heat flux (CHF) is substantially important that in truth, it has been obtained with a numerical thermal analysis. Using the look up table method, the location of CHF has been determined for pure water and all nanofluids. According to obtained results for two types of mass fluxes and in along increasing of volumetric concentration from 0 up to 2% for gold nanoparticles, tube temperature in its internal surface has been decreased that it has been equaled 1.33 and 0.34% for mass fluxes 100 and 500 kg/ m~2 s, respectively. Also, length of CHF has been increased equal to 91.01 and 114.1% for mentioned mass fluxes. On the other hand, an increasing has been acquired about convection heat flux in CHF point that they are 1.49 and 0.28%.