Thermo-hydraulic performance of solar air heater having discrete D-shaped ribs as artificial roughness

Nitesh Dutt; Ankush Jageshwar Hedau; Ashwani Kumar; Mukesh Kumar Awasthi; Varun Pratap Singh; Gaurav Dwivedi

doi:10.1007/s11356-023-28247-9

Thermo-hydraulic performance of solar air heater having discrete D-shaped ribs as artificial roughness

Environ Sci Pollut Res Int. 2023 Jul 5. doi: 10.1007/s11356-023-28247-9. Online ahead of print.

Authors

Nitesh Dutt¹, Ankush Jageshwar Hedau², Ashwani Kumar³, Mukesh Kumar Awasthi⁴, Varun Pratap Singh⁵, Gaurav Dwivedi⁶

Affiliations

¹ Department of Mechanical Engineering, College of Engineering Roorkee, COER University, Roorkee, Uttarakhand, India.
² Department of Hydro and Renewable Energy, IIT Roorkee, Roorkee, India. ankush.hedau@gmail.com.
³ Technical Education Department, Uttar Pradesh, Kanpur, India.
⁴ Department of Mathematics, Babasaheb Bhimrao Ambedkar University, Lucknow, India.
⁵ Department of Mechanical Cluster, School of Engineering, University of Petroleum and Energy Studies, Dehradun, India.
⁶ Energy Centre, Maulana Azad National Institute of Technology, Bhopal, 462003, India.

PMID: 37407860
DOI: 10.1007/s11356-023-28247-9

Abstract

In this paper, the thermo-hydraulic performance of a solar air heater (SAH) duct roughened with discrete D-shaped ribs is numerically investigated using ANSYS Fluent 2020 R₂. The numerical investigation is carried out at rib radius to transverse pitch ratio (r/P_t) from 0.1 to 0.35 and longitudinal pitch to rib radius ratio (P_l /r) from 4 to 10 under various operating conditions with Reynolds number (Re) varied from 10,200 to 20,200. The numerical results are validated with previous experimental results for the Nusselt number (Nu) values, and good agreement is found with mean absolute percentage error (MAPE) of 3.6%. Based on the results of the numerical investigation, it was found that the value of Nu and the friction factor (f) decreases with the increase of the value of P_l/r, while the ratio r/P_t is kept constant. From the overall analysis, it is concluded that the optimum results are obtained for r/P_t of 0.25 and P_l/r = 4, and the maximum thermo-hydraulic performance parameter is 1.12. Further correlations are developed for the value of Nu and f for the whole range of r/P_t as 0.10-0.35 and P_l/r as 4-10. According to the developed correlations, the values of Nu are within ± 2% of the results of CFD, while the values of f are within ± 2.7% of the results of CFD.

Keywords: Artificial roughness; Discrete D-shaped rib; Heat transfer; Solar air heater; Solar energy; Thermo-hydraulic performance parameter.