Thermal Performance Enhancement Using Absorber Tube with Inner Helical Axial Fins in a Parabolic Trough Solar Collector

Mohammad Zaboli,Mohsen Saffari Pour,Seyfolah Saedodin,Seyed Soheil Mousavi Ajarostaghi

doi:10.3390/app11167423

Abstract

In the present work, a parabolic trough solar (PTC) collector with inner helical axial fins as swirl generator or turbulator is considered and analyzed numerically. The three-dimensional numerical simulations have been done by finite volume method (FVM) using a commercial CFD code, ANSYS FLUENT 18.2. The spatial discretization of mass, momentum, energy equations, and turbulence kinetic energy has been obtained by a second-order upwind scheme. To compute gradients, Green-Gauss cell-based method has been employed. This work consists of two sections where, first, four various geometries are appraised, and in the following, the selected schematic of the collector from the previous part is selected, and four various pitches of inner helical fins including 250, 500, 750 and 1000 mm are studied. All the numerical results are obtained by utilizing the FVM. Results show that the thermal performance improvement by 23.1% could be achieved by using one of the proposed innovative parabolic trough solar collectors compare to the simple one. Additionally, the minimum and maximum thermal performance improvement (compare to the case without fins) belong to the case with P = 250 mm by 14.1% and, to the case with P = 1000 mm by 21.53%, respectively.

Highlights

Accepted: 2 August 2021Heat exchangers, which transfer thermal energy through direct and indirect contact between fluids, are considered an indispensable part of several industries, from pharmaceutical to petrochemicals
Abolarin et al [15] have checked the impact of various geometries in twisted tapes, and the results pointed out that connection angle increases heat transfer
Ghasemi and Ranjbar [43] in the numerical verification on solar parabolic collector demonstrated that adding nanoparticles increase thermal performance and using Al2 O3 or CuO as nanofluid at 3% volume fraction enhances the heat exchange up to 28 and 35 percent, respectively

Summary

Introduction

Heat exchangers, which transfer thermal energy through direct and indirect contact between fluids, are considered an indispensable part of several industries, from pharmaceutical to petrochemicals. One of two categories of ameliorating heat exchange methods is passive procedures [2] It means that there is no requirement for any type of additional force. Tang et al [10] checked the heat transfer in the heat exchanger According to their results, an increase of length enhances the performance of the vortex-generator fin. Abolarin et al [15] have checked the impact of various geometries in twisted tapes, and the results pointed out that connection angle increases heat transfer.

Result

Governing Equations and Dimensionless Parameters

Grid Independency Study

Validation Study

The Impact of the Schematic of the Proposed Collector’s Fins

Conclusions and Future Scope