标题：Effect of volume fraction and size of Al2O3 nanoparticles in thermal, frictional and economic performance of circumferential corrugated helical tube
摘要：The economic and operational constraints are the most important ones when it comes to decide to use any performance enhancement method. In this paper, the effect of Al 2 O 3 Nano-particle on the economic, thermal and entropic and beneficial of the coiled heat exchanger tube. The Nano-particles volume fraction and diameter were considered as the major variants. Four volume fractions of 0.01, 0.02, 0.03 and 0.04 as well as to three diameter size of 10 nm, 20 nm and 30 nm were considered in this study. The coiled heat exchanger was considered to be under constant wall temperature and the process was considered to be steady. The results presented that variation of volume fraction has significant effect on the friction factor whereas the variation of particle size did not show a significant influence. Also, it was found that the increment of volume fraction could bring up to 31% increment in the Nusselt number. Evaluation of Performance evaluation factors (PEC) revealed that the compound usage of corrugation and Nano-particle could lead in about 29% enhancement in the performance index. Furthermore, evaluation of economic parameter of Net Profit per Unit Transferred Heat Load ( η p ) depicted that simultaneous usage of corrugation and Nano-particles enlarges the range of Dean number at which the system was economically beneficial. The expansion was up to 66% and the best case was related to volume fraction of 0.01.
