Abstract:This article presents the use of a wire mesh in optimising the performance of two volumetric solar receivers that use oil as a heat transfer fluid. Computational fluid dynamics models have been used to optimise the receivers. Varied parameters (including the use of a wire mesh) of the receiver models were changed in the optimisation process. Based on the models, prototype receivers were developed and tested. After that, the models were validated against experiments and the results compare well. The results ind… Show more
“…On the other hand, fins significantly impacted the heat transfer and temperature development; they can enhance heat transfer from solid to fluid surfaces [ 25 ]. Adding further fins was reported to cause a drop in the peak temperature of the receiver tube [ 26 ]. The highest maximum temperature found for the smooth tube with Re = 14000 equalled 691 K. As the number of fins increased the maximum temperature decreased, and the lowest maximum temperature was 617 K when N = 20 and Re = 38000.…”
Section: Resultsmentioning
confidence: 99%
“…The efficiency is always higher with any number of fins compared with the smooth tube; these differences in efficiency illustrate the substantial impact of fins. The efficiency increases with a higher Reynolds number, and this is related to lower thermal losses and higher mass transfers with a high mass flow rate [ 26 ]. Figure 10 Receiver efficiency with different numbers of fins, N = 1,7 &20.…”
The solar receiver is considered the cornerstone of the solar tower power system. In particular, it receives hightemperature heat flux rays, and extracts the maximum heat energy to be transferred to the heat transfer fluid, while minimising any thermal and mechanical stresses. Reducing the solar receiver size helps to reduce the loss of spillage; consequently, the thermal stress increases. Using a solar receiver with inserted triangular longitudinal fins enhances the heat transfer as well as strengthens the receiver tube. This study aims to optimise the number of fins, heat flux aiming point, heat transfer fluid, nanoparticle effect with molten salt as the base fluid, and type of receiver material. Non-uniform heat flux with the cosine and Gaussian effects have been considered. When the number of fins (N) increases, the maximum temperature (T max ) decreases and the heat transfer is enhanced. When N ¼ 20, T max ¼ 656.4 K and when N ¼ 1, T max ¼ 683.55, while the efficiency for N ¼ 1 is greater by 3% compared to when N ¼ 20. The cosine distribution of heat flux has a higher maximum temperature than the Gaussian distribution by 29% and is 102% higher in receiver efficiency. The thermal efficiency when the heat flux is aimed at the middle point of the receiver is higher by 10% compared with a lower or upper aiming point. Using Al 2 O 3 nanoparticles with a concentration of 0.5 wt.% increases the thermal efficiency by 14% more than when using pure molten salt when Re ¼ 38000. Using liquid sodium is not required to monitor the peak heat flux, and by adding triangular fins the displacement and thermal stress are 6.5 % lower compared to a smooth receiver.
“…On the other hand, fins significantly impacted the heat transfer and temperature development; they can enhance heat transfer from solid to fluid surfaces [ 25 ]. Adding further fins was reported to cause a drop in the peak temperature of the receiver tube [ 26 ]. The highest maximum temperature found for the smooth tube with Re = 14000 equalled 691 K. As the number of fins increased the maximum temperature decreased, and the lowest maximum temperature was 617 K when N = 20 and Re = 38000.…”
Section: Resultsmentioning
confidence: 99%
“…The efficiency is always higher with any number of fins compared with the smooth tube; these differences in efficiency illustrate the substantial impact of fins. The efficiency increases with a higher Reynolds number, and this is related to lower thermal losses and higher mass transfers with a high mass flow rate [ 26 ]. Figure 10 Receiver efficiency with different numbers of fins, N = 1,7 &20.…”
The solar receiver is considered the cornerstone of the solar tower power system. In particular, it receives hightemperature heat flux rays, and extracts the maximum heat energy to be transferred to the heat transfer fluid, while minimising any thermal and mechanical stresses. Reducing the solar receiver size helps to reduce the loss of spillage; consequently, the thermal stress increases. Using a solar receiver with inserted triangular longitudinal fins enhances the heat transfer as well as strengthens the receiver tube. This study aims to optimise the number of fins, heat flux aiming point, heat transfer fluid, nanoparticle effect with molten salt as the base fluid, and type of receiver material. Non-uniform heat flux with the cosine and Gaussian effects have been considered. When the number of fins (N) increases, the maximum temperature (T max ) decreases and the heat transfer is enhanced. When N ¼ 20, T max ¼ 656.4 K and when N ¼ 1, T max ¼ 683.55, while the efficiency for N ¼ 1 is greater by 3% compared to when N ¼ 20. The cosine distribution of heat flux has a higher maximum temperature than the Gaussian distribution by 29% and is 102% higher in receiver efficiency. The thermal efficiency when the heat flux is aimed at the middle point of the receiver is higher by 10% compared with a lower or upper aiming point. Using Al 2 O 3 nanoparticles with a concentration of 0.5 wt.% increases the thermal efficiency by 14% more than when using pure molten salt when Re ¼ 38000. Using liquid sodium is not required to monitor the peak heat flux, and by adding triangular fins the displacement and thermal stress are 6.5 % lower compared to a smooth receiver.
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