Numerical investigation of the effect of enforced air flow in a closed cavity on temperature distribution of ammonium dihydrogen phosphate crystal with a large aperture

Abstract

The temperature distribution of a novel Final optics assembly (FOA) made of a square ammonium dihydrogen phosphate (ADP) crystal with a large aperture is examined numerically in this noncritical phase-matching simulation (NCPM). The temperature of the cavity wall is maintained by temperature-controlled, continuously flowing (0.1 m/s) water (313.5 k). The thermal study was first performed numerically inside the cavity with different configurations using the finite volume technique. One fan was placed on one side of the ADP crystal to evaluate the temperature distribution within the cavity and between the crystals. The fan speed is then varied from 10 to 40 rad/s with a step interval of 10 rad/s to evaluate the effect of forced convection. Furthermore, the investigation showed that 20 rad/s is more effective than the other cases. To measure the impact of temperature distribution caused by fan orientation, the fan orientation was adjusted to three different tilt angles (10, 20, and 30 degrees) while the fan rotational speed was maintained at 20 rad/s. The two fans on the side and the two fans on either side of the ADP crystal were also investigated, with different orientations (0, 10, and 20 degrees) and speeds (0, 10, 20, 30, and 40 rad/s). According to the fan speed, direction, number of speeds, and fan locations, the high-temperature spot of ADP crystals can be symmetric, asymmetric, diagonally dominant, center dominant, bottom dominant, or top dominant.