TY - JOUR
TI - Computational study of laminar free convection inside tilting irregular cavity of a batch-type solar collector
AU - Butt Fahad Sarfraz
AU - Badar Abdul Waheed
AU - Janjua Ajaz Bashir
AU - Siddiqui M Salman
JN - Thermal Science
PY - 2022
VL - 26
IS - 1
SP - 423
EP - 435
PT - Article
AB - Batch-type solar collector is a tilt-able water-heating solar-thermal system comprising an isosceles-trapezoidal enclosure housing a circular-cylinder absorber at the bottom wall, insulated side-walls, and flat-top glazing. Free convection of air inside such trapezoidal enclosure is studied numerically by varying the tilt angle of the whole enclosure from 0°-70°. The influence of tilt on the flow field has been demonstrated by plotting the streamlines and isotherms. The present study successfully identifies the importance of enclosure-tilt in quantifying heat-loss between absorber and glazing by developing a computational correlation between Nusselt and Rayleigh as a function of tilt. The correlation trend is non-monotonic over the range of angular Rayleigh numbers numerically experimented with having a peak around angular Rayleigh number 3⋅105 corresponding to the tilt-angle 30°. The irregular-shaped cavity implies that the heat transfer correlations already existing for regular-shaped cavities may not be used otherwise they will draw implausible conclusions and this argument identifies the novelty of the present study.