Design and analysis of constant volume optical chamber for spray and combustion characterization

Abstract

Constant volume chambers with good optical access are widely used for spray visualization and combustion analysis due to better reproducibility of the thermodynamic conditions and large visualization area. Hence optically accessible test rigs are developed worldwide both in academia and industry for investigations. The prime objective of any optical test rig for the spray and combustion study is to create ambient conditions that are representative of those in an actual engine during the injection and combustion process. In the present work, a constant volume optical chamber is designed and tested computationally for its resistance against structural and thermal loads. The chamber is made of stainless steel SS304 with four Quartz windows on the sides for optical access. The chamber is designed to withstand a maximum pressure of 6 MPa at a temperature of 900 °C. After the analytical design, static structural and thermal simulations are carried out. The geometrical design is made in solid works. The computational simulation is done using ANSYS 19.2 using structural and thermal packages. The results are compared with the permissible yield strength of the material, considering a factor of safety of 2. It is observed that for all components, the materials experience stress which is below its permissible yield stress. The thermal analysis results also suggest that the exposed surface of the chamber does not exceed a temperature of 79 °C, indicating good operating safety.