Numerical Study of New-Type Receiver with Axially-Hollow Spiral Deflector for Parabolic Trough Direct-Steam-Generation Loop of Concentrating Solar Power System

The thermal stress-induced deformation issue of receiver is crucial to the performance and reliability of a parabolic-trough (PT) concentrating solar power (CSP) system with the promising direct steam generation (DSG) technology. The objective of the present study is to propose a new-type receiver with axially-hollow spiral deflector and optimize the geometric structure to solve the above issue. To this end, optical-flow-thermal multi-physics coupling models have been established for the preheating, boiling and superheating sections of a typical PT-DSG loop. The simulation results show that our proposed new-type receiver demonstrates outstanding comprehensive performance. It can minimize the circumferential temperature difference through the spiral deflector while lower the flow resistance cost through the axially hollow structure at the same time. As quantitatively evaluated by the temperature uniformity improvement (ε_ΔT) and the performance evaluation criteria (PEC), different designs are achieved based on different optimal schemes. When ε_ΔT is of primary importance, the optimal design with torsional ratio of 1 is achieved, with ε_ΔT=25.4%, 25.7%, 41.5% and PEC=0.486, 0.878, 0.596 corresponding to preheating, boiling, superheating sections, respectively. When PEC is of primary importance, the optimal design with torsional ratio of 6–6.5 is achieved, with PEC=0.950, 2.070, 0.993 and ε_ΔT=18.2%, 13.3%, 19.4% corresponding to preheating, boiling, superheating sections, respectively.