Abstract:
The solar air collector is an important component of the solar drying system, and the structure design of the collector has an important impact on the heat collection performance. In this paper, a basic baffle collector was designed, and the outlet temperature of the collector under certain boundary and material parameters was tested through a solar simulator. A three-dimensional solid model of the collector was constructed based on Solidworks and Comsol, and the collector’s heat collection performance was numerically investigated using the realizable-k-ε turbulence model. The results showed that the relative error between the test value of the outlet temperature and the simulated value was less than 0.70%, and the numerical simulation was effective and reliable. Based on the BBD(Box-Behnken Design) test and response surface method, the effect of different inclination angle combinations of baffles on the collector performance was investigated, and the best combination of parameters was obtained by analyzing the test results: the inclination angle of baffle 1 is-10°, the inclination angle of baffle 2 is 10°, the inclination angle of baffle 3 is-10°, and the inclination angle of baffle 4 is 10°, which was used to optimize the collector baffles arrangement and obtain an inclination baffles collector. Compared with the basic baffle collector, the outlet temperature of the inclined baffle collector was increased by 1.63 K, the heat collection efficiency was increased by 4.01%, and the inlet and outlet pressure loss was reduced by 44.80%. Based on the fluid bypass effect, several circular holes were drilled in the baffles to further optimize the heat accumulation and flow field distribution of the heat-absorbing plate, and an open-hole type inclined baffle heat collector is obtained. Compared with the basic baffle collector, the outlet temperature of the open-hole type inclined baffle collector was increased by 2.03 K, the heat collection efficiency was increased by 4.99%, and the inlet and outlet pressure loss were reduced by 43.13%. A single-factor simulation test was carried out on the inlet air speed conditions of the open-hole type inclined baffle collector, and a better inlet air speed condition was obtained, i.e., 0.5-1.0 m/s, which meets the requirements of agricultural solar drying.