Experimental Study of a Single Quartz Tube Solid Particle Air Receiver

Abstract

Abstract This article presents an experimental evaluation of a specially designed quartz tube solid particle air receiver. A new air intake tube was designed, which is conducive to realize solid particlesfluidizationinside a quartz tube under lowerinlet airflow rate and very few particles were blown out of the receiver during operation. With the air intake tube, a single quartz tube solid particle air receiver was designed and manufactured. Concentrated solar radiation was absorbed and converted into thermal energy in an air flow by particles inside the receiver. Multi-condition experiments have been done to test the dynamic thermal performance of the receiver on a 10 kW th solar furnace system. Experimental research focuses on the effect on the particle-air bulk temperature and outlet air temperature and their temperature difference with different particle diameters, particle volume fractions and inlet airflow rates. During the experiments, the maximum outlet air temperature obtained was 598.9 °C, and in some working conditions the average temperature differences between particle-air bulk and outlet air were less than 50 °C, showing good convective heat transfer between particles and air. The experiments resulted in the following conclusions: (1) smaller particles may lead to lower temperature difference between particle-air bulk and outlet air due to large specific surface area, (2) larger particle volume fraction leads to lower particle-air bulk and outlet air temperature difference, however, excessiveparticles cause poor fluidization state and heat transfer between particles and air, and thus higher temperature difference, (3) on condition that the particles and air are evenly mixed, higher inlet air massflow rate results in lower temperature difference between particle-air bulk and outlet air. Besides, the fluidized state inside thereceiver is dependent not only on the inlet air mass flow rate but also on the particle-airbulk temperature. The accumulated operating time of the receiver exceeded 20 hours without any major failure.