THERMAL PERFORMANCE ANALYSIS OF ARTIFICIALLY ROUGHENED SOLAR AIR HEATER USING CFD
Author(s):
Shahrukh Khan, Prof. Rohit Soni
Keywords:
Solar Air Heater, Artificial Roughness, Rib, Absorber Plate, ANSYS 14.5, Reynold’s number, Nusselt number, CFD, Fluent.
Abstract
The twenty-first century is forming into the perfect energy storm. Rising energy prices, diminishing energy availability and security, and growing environmental concerns are quickly changing the global energy panorama. Energy and water are the keys to modern life and provide the basis necessary for sustained economic development. Industrialized societies have become increasingly dependent on fossil fuels for myriad uses. Modern conveniences, mechanized agriculture, and global population growth have only been made possible through the exploitation of inexpensive fossil fuels. Finding sufficient supplies of clean and sustainable energy for the future is the global society’s most daunting challenge for the twenty-first century. The future will be a mix of energy technologies with renewable sources such as solar, wind, and biomass playing an increasingly important role in the new global energy economy.
In the present work attempts are made to performed to study the effects of different rib shapes on heat transfer and fluid flow characteristics through transversely roughened rectangular channels for Reynolds number ranging from 3800 to 15,000 and subjected to uniform heat flux of 1000 W/m2 using CFD.Considering single-phase approach, the three-dimensional continuity, Navier-Stokes, and energy equations developed for the physical model have been solved by using the finite volume method (FVM). The optimization was carried out by using various Rib shapes (X-section rib channel & Square section rib channel) in in-line and different aspect ratios (Dh=33.33, Aspect ratio of duct W/H=5, Relative roughness pitch P/e=7.14, Relative roughness height e/D=0.042) to reach the optimal geometry of the rib with maximum Performance Evaluation Criterion (PEC). The highest PEC was obtained for the X-section rib at Re =3800 is 1.703. For the X-section rib channel, the increase in average Nusselt number value is about 162.48% more than the smooth channel and the use of the X-section rib channel compare with Square section rib channel shows a higher average Nusselt number around 17.70%.
