Numerical Study of Flow and Heat Transfer in Cavity Receiver Tube of a Solar Power Tower with Different Inserts under Non-uniform Heat flux

Document Type : Original Article

Authors

• Siavash Zeynalpour
• Zahra Mehrdoost

Department of Mechanical Engineering,Ahvaz Branch, Islamic Azad University, Ahvaz, Iran

10.22067/jacsm.2022.76201.1111

Abstract

In this paper, the effect of using four different types of inserts in cavity receiver tube of solar power tower to improve heat transfer and reduce non-uniform temperature distribution is investigated. Numerical simulation is performed in three dimensions and the effect of inserts configurations, position inside receiver tube, pitch and thickness of insert and the effect of non-uniform heat fluxon the Nusselt number, friction factor and temperature of outer surface of receiver tube are investigated. The flow is incompressible, steadystate, turbulent and the Reynolds number is in the range of 8000 to 20000. Numerical simulation results for four types of inserts: twisted-tape, wavy-tape, helical-tape and louvered-tape show that wavy-tape compared to the other three types, has the higher Nusselt number and the lower average temperature of receiver tubesurface. The Nusselt number of the wavy-tape is increased by 1.8%, 2% and 3.2% relative to the louvered-tape, twisted-tape and helical-tape, respectively and 10% relative to the receiver tube without insert. By increasing the insert thickness and decreasing the insert pitch, the Nusselt number increases and average temperature of receiver tubesurface decreases. Investigating the insert position in three cases: close to the non-uniform heat flux wall, the middle of the tube and close to the insulation wall show that by increasing the distance of insert from non-uniform heat flux wall, the mixing of hot and cold fluids flow is better and the temperature distribution is more uniform.Therefore, the best position to place insert is the farthest distance from the non-uniform heat flux wall.

Keywords

• Solar power tower
• cavity receiver tube
• non-uniform heat flux
• insert
• heat transfer

Main Subjects

• Heat transfer

---

References

[1] Dutta, "High temperature solar receiver and thermal storage systems", Applied Thermal Engineering, vol. 124, pp. 624–632, (2017).

[2] L. Zhang, J. Fang, J. Wei and G. Yang, "Numerical investigation on the thermal performance of molten salt cavity receivers with different structures", Applied Energy, vol. 204, pp. 966–978, (2017).

[3] Z. Liao, X. Li, C. Xu, C. Chang and Z. Wang, "Allowable flux density on a solar central receiver", Renewable Energy, vol. 62, pp. 747–753, (2014).

[4] C.K. Ho and B.D. Iverson, "Review of high-temperature central receiver designs for concentrating solar power", Renewable & Sustainable Energy Reviews, vol. 29, pp. 835–846, (2014).

[5] Y. Hao, Y. Wang and T. Hu, "The flow distribution in the parallel tubes of the cavity receiver under variable heat flux", Applied Thermal Engineering, vol. 108, pp. 641–649, (2016).

[6] S.M. Besarati, D. Yogi Goswami and E.K. Stefanakos, "Optimal heliostat aiming strategy for uniform distribution of heat flux on the receiver of a solar power tower plant", Energy Conversion and Management, vol. 84, pp. 234–243, (2014).

[7] Q. Yu, Z. Wang and E. Xu, "Analysis and improvement of solar flux distribution inside a cavity receiver based on multi-focal points of heliostat field", Applied Energy, vol. 136, pp. 417–430, (2014).

[8] N. Tu, J. Wei and J. Fang, "Numerical investigation on uniformity of heat flux for semi-gray surfaces inside a solar cavity receiver", Solar Energy, vol. 112, pp. 128–143, (2015).

[9] M. Binotti, P.D. Giorgi, D. Sanchez and G. Manzolini, "Comparison of different strategies for heliostats aiming point in cavity and external tower", Journal of Solar Energy Engineering, vol. 138, pp. 021008-1–021008-11, (2016).

[10] A. Salomé, F. Chhel, G. Flamant, A. Ferrière and F. Thiery, "Control of the flux distribution on a solar tower receiver using an optimized aiming point strategy: Application to THEMIS solar tower", Solar Energy, vol. 94, pp. 352–366, (2013).

[11] T. Ashley, E. Carrizosa and E. Fernández-Cara, "Optimisation of aiming strategies in solar power tower plants", Energy, vol. 137, pp. 285–291, (2017).

[12] K. Wang, Y.L. He, Y. Qiu and Y. Zhang, "A novel integrated simulation approach couples MCRT and Gebhart methods to simulate solar radiation transfer in a solar power tower system with a cavity receiver", Renewable Energy, vol. 89, pp. 93–107, (2016).

[13] J. Pacio and T. Wetzel, "Assessment of liquid metal technology status and research paths for their use as efficient heat transfer fluids in solar central receiver systems", Solar Energy, vol. 93, pp. 11–22, (2013).

[14] L. Marocco, G. Cammi, J. Flesch and T. Wetzel, "Numerical analysis of a solar tower receiver tube operated with liquid metals", International Journal of Thermal Sciences, vol. 105, pp. 22–35, (2016).

[15] C. Zou, Y. Zhang, Q. Falcoz, P. Neveu, C. Zhang, W. Shu, and S. Huang, "Design and optimization of a high-temperature cavity receiver for a solar energy cascade utilization system", Renewable Energy, vol. 103, pp. 478–489, (2017).

[16] L. Yang, R. Zhou, Jin, X., Ling, X., Peng, H., "Experimental investigate on thermal properties of a novel high temperature flat heat pipe receiver in solar power tower plant", Applied Thermal Engineering, vol. 109, pp. 610–618, (2016).

[17] K. Kanatani, T. Yamamoto, Y. Tamaura and H. Kikura, "A model of a solar cavity receiver with coiled tubes", Solar Energy, vol. 153, pp. 249–261, (2017).

[18] A. Mwesigye, T. Bello-Ochende and J.P. Meyer, "Heat transfer and thermodynamic performance of a parabolic trough receiver with centrally placed perforated plate inserts", Applied Energy, vol. 136, pp. 989–1003, (2014).

[19] Y. Liu, W-J. Ye, Y-H. Li and J-F. Li, "Numerical analysis of inserts configurations in a cavity receiver tube of a solar power tower plant with non-uniform heat flux", Applied Thermal Engineering, vol. 140, pp. 1–12, (2018).

[20] M. Allam, M. Tawfik, M. Bekheit and E. El-Negiry, "Heat transfer enhancement in parabolic trough receivers using inserts: A review", Sustainable Energy Technologies and Assessments, vol. 28, (2021).

[21] P. Liu, Z. Dong, H. Xiao, Z. Liu and W. Liu, "A novel parabolic trough receiver by inserting an inner tube with a wing- like fringe for solar cascade heat collection", Renewable Energy, vol. 170, pp. 327-340, (2021).

[22] Y. Qiu, M. Li, M-J. Li, H. Zhang and B. Ning, "Numerical and experimental study on heat transfer and flow features of representative molten salts for energy applications in turbulent tube flow", International Journal of Heat and Mass Transfer, vol. 135, pp. 732-745, (2019).

[23] W.Q. Tao, Numerical Heat Transfer, second ed., Xi’an Jiaotong University Press, Xi’an, (2001).

[24] P. Schwarzbölz, M. Schmitz and R. Pitz-Paal, Visual HFCAL – a software for layout and optimization of heliostat fields, Solar PACES, Berlin, (2009).

[25] F.J. Collado, "One-point fitting of the flux density produced by a heliostat", Solar Energy, vol. 84(4), pp.673–684, (2010).

[26] V. Gnielinski, "New equations for heat and mass transfer in turbulent pipe and channel flow", International Journal of Chemical Engineering, vol. 16, pp. 359–368, (1976).