Thermal improvement of linear Fresnel solar system utilizing Al2O3-water nanofluid and multi-way twisted tape

To enhance the thermal treatment of Linear Fresnel Reflector (LFR) unit, multi-way twisted tape (MWTT) was applied in current research. Twelve mirrors and one tube with trapezoidal cavity around it, generates new LFR unit. The operating fluid is Al2O3-water and for predicting the properties, temperature dependent formulas were employed. Finite volume simulations results in finding the distribution of velocity, temperature, entropy generation. Also, thermal performance was measured. The geometrical factors are number of wings (n(w)), revolution (TR) and width (ER) of tapes. To evaluate the modeling procedure, various examinations with numerical and experimental publications were verified. To extract the distribution of absorb flux, SolTrace and ANSYS FLUET have been utilized and they are in good agreement. The output of SolTrace demonstrates the path of rays and selecting higher number of rays results in higher accuracy. Highest absorb flux occurs in bottom of pipe. As mixing of fluid improves with rise of revolution and width of tapes, Nu increases and augmentation in interaction of fluid with wall enhances the friction factor. Increasing number of wings can enhance the secondary flow. So, stronger impingement with wall can augment the friction factor. Nu enhances with rise of n(w) about 4.384% when TR = 2, ER = 0.34, V = 19. Augmenting TR makes Nu to increase about 7.135% when n(w) = 4, ER = 0.1, V = 19. Besides, with selecting higher ER, friction factor augments about 20.019% at TR = 2, n(w) = 2, V = 6.3. To evaluate the amount of available work of this solar unit, components of entropy generation (S-gen,S-f,S- S-gen,S-h) have been measured. Thermal irreversibility declines with increase of turbulent intensity while friction component increases. Thermal efficiency (eta th) augments with growth of TR, ER and n(w) while it decreases with enhance of inlet temperature. As Tin rises, eta threduces about 31.51% when TR = 2, n(w) = 2, ER = 0.1, (V)over dot = 19. Inclusion of nano-powders can enhance the useful heat and eta thaugments about 0.153%.

Automated summary

In this study, the thermal treatment of Linear Fresnel Reflector (LFR) unit was enhanced by the application of multi-way twisted tape (MWTT). Finite volume simulations were used to predict the flow and thermal performance, and SolTrace and ANSYS FLUET were used to extract the distribution of absorb flux. The results showed that the rotation, width, and number of wings of the twisted tape significantly affected the fluid flow and thermal efficiency.