Thermal performance assessment of internal longitudinal fins with sinusoidal lateral surfaces in parabolic trough receiver tubes. (September 2019)

• Record Type: Journal Article
• Authors: Kurşun, Burak
• Is Part Of: Renewable energy. Volume 140(2019)
• Page Start: 816
• Page End: 827
• Publication Date: 2019-09
• Subjects: Flat fin -- Sinusoidal fin -- Parabolic trough -- Thermal enhancement; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2019.03.106
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: In this study, the effect of the internal longitudinal fins with the flat and sinusoidal lateral surface on the thermal performance of the parabolic trough receiver tube was investigated. Nusselt number (Nu), friction coefficient (f), thermal enhancement factor (ψ) and circumferential temperature difference (ΔTmax ) were evaluated by the numerical analyzes. Analyzes were carried out using the different amplitude (a) and periodic length (p) values of the sinusoidal geometry for the different Reynolds numbers (Re). It was observed that the most important factors affecting the heat transfer were the fluid inlet temperature (Tin ) and the a value. The highest enhancement in the Nu was found to be 25% and 78% for the flat and sinusoidal fin, respectively. The ΔTmax with the sinusoidal lateral surface geometry decreased in the range of 66–164 K. With the increase in the Re, the ψ remained approximately constant for the flat fin geometry (ψ ≈ 1, 43). For the sinusoidal lateral surfaces, the ψ fell below 1 in high amplitude and Re values. For the Tin in the range of 300–600 K, the ψ value in the range of 0.85–2.32 were obtained. The results of the analysis revealed that the sinusoidal lateral surface geometry contributes to the heat transfer enhancement. Highlights: This paper presents the use of longitudinal internal fin with sinusoidal surface for parabolic trough receiver tubes. Sinusoidal lateral surface geometry directed the fluid to different directions and the convection near the fins increased. The highest enhancement in the Nu was observed to be 78% for the fin with the sinusoidal lateral surface. The circumferential temperature difference with the sinusoidal lateral surface geometry decreased in the range of 66–164 K. It was determined that the thermal enhancement factor was higher in low Re number values.