Investigation of Heat Transfer Characteristics of Line Focus Receiver with Porous Disc Inserts for Solar Parabolic Trough Concentrator
K. Ravi Kumar and K. S. Reddya
Heat Transfer and Thermal Power Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600 036, Tamil Nadu, India.
aksreddy@iitm.ac.in
ABSTRACT
In this article, heat transfer characteristics of line focus porous disc receiver for a solar parabolic trough concentrator is presented. The three dimensional numerical simulations of porous disc receiver with water as working fluid are carried out using commercial CFD package, FLUENT 6.3 and it is solved by renormalization-group (RNG) k−ε turbulent model associated with standard wall function. The top and bottom receiver surfaces are subjected to net heat flux conditions to simulate exactly concentrated solar radiation condition. The effect of porous disc geometric parameters such as porosity(φ) inclination (θ), configuration (co), height (h), pitch (w), thickness (t) on heat transfer characteristics is studied. It is found that receiver with bottom porous disc at porosity 0.4, inclination 30°, height 0.5d, pitch d, thickness 2 mm, and Reynolds number of 11,750 showed better heat transfer characteristics as compared to other receiver configurations. The porous disc receiver enhances heat transfer rate of 438 W/m length of the receiver and 27.4% with pumping penalty of 0.056 W/m length as compared to the tubular receiver. Nusselt number correlation is proposed for the range of parameters considered for the porous disc receiver. The porous disc receiver can be used efficiently for solar medium temperature applications.
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