Wavy-tape insert designed for managing highly concentrated solar energy on absorber tube of parabolic trough receiver

In this paper, a swirl flow generator, namely wavy-tape insert, is tailored for the parabolic trough receiver (PTR) to improve its performances by mean of enhancing the heat transfer inside the absorber tube. A comprehensive computational fluid dynamics model is established to study the flow and heat transfer inside the full-size PTR equipped with wavy-tape insert. It is found that wavy-tape provokes highly-localized heat transfer enhancement effects, which exactly aim at the highly-concentrated solar heat load. Consequently, both the tube temperature and the heat loss are reduced effectively. A static mechanical analysis is performed to evaluate the thermal stress and deformation of absorber tube, both of which decrease in the presence of wavy-tape. However, the wavy-tape improves the PTR thermal-mechanical performances at the expense of increased pressure loss penalty. The overall effects of wavy-tape insert on PTR are evaluated based on different criterions. For a same flow rate, the total entropy generation rate can be reduced significantly by using wavy-tape insert. For an identical pumping power consumption, the insert not only reduces the thermal stress and the heat loss, but also gives raises to the specific enthalpy gain of the working fluid.