Experimental investigation of the effects of wind speed and yaw angle on heat losses from a heated cavity. (1st May 2018)

• Record Type: Journal Article
• Authors: Lee, Ka Lok; Chinnici, Alfonso; Jafarian, Mehdi; Arjomandi, Maziar; Dally, Bassam; Nathan, Graham
• Is Part Of: Solar energy. Volume 165(2018)
• Page Start: 178
• Page End: 188
• Publication Date: 2018-05-01
• Subjects: Solar receiver -- Solar thermal power -- Heat loss -- Concentrated solar thermal -- Temperature distribution -- Wind; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2018.03.023
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: Effects of wall temperature on heat loss from a temperature controlled solar receiver. Effect of wind speed and direction on heat loss from a heated cavity. The distribution of heat loss from the different parts of the solar cavity receiver. Abstract: An experimental investigation of the effects of wind speed (0–12 m/s) and yaw angle (0°–90°) on the convective heat losses from a cylindrical cavity heated with a uniform wall temperature, is presented. The cavity is heated with 16 individually controlled copper surface elements, so that both the heat losses and the heat flux distribution can be measured and subjected to a controlled convective environment in the open section of a wind tunnel. It was found that the convective heat losses through the aperture are ∼4 times greater for the head-on wind case than for the side-on wind case, when the inverse of Richardson number ( 1 / Ri ) > 77 (wind speed >12 m/s). For the no-wind condition, ≈85% of the heat was lost from the lower half of the surface of the cavity, while for 1 / Ri > 43 (wind speed >9 m/s), the heat loss was more uniformly distributed over the surface of the cavity. For head-on-wind conditions and for 1 / Ri > 19 (wind speeds >6 m/s), the convective heat losses are ∼2 times greater than for side-wind conditions. The correlations between the mixed (natural and forced) convective heat losses, Nusselt number and Richardson number are also reported.