Heat Exchange and Operating Gas Flow Influence on Radiation Resistant Pressure Sensor Properties

A novel pressure sensor is investigated numerically. Operation of this sensor is determined by mechanical stresses and heat exchange. Estimation of deformations and heat transfer was done using programs ANSYS and ANSYS CFX. Numerical model was calibrated to fit experimental results. Conclusions about significance of heat exchange, thermal stresses and overall action of sensor were made. 1. General information A novel concept for measuring pressures in conditions which requires resistance against radiation is developed in PSI, but it still needs further investigation and numerical simulation. It is important to find parameters for sensor to ensure pressure measurements with certain precision in 1-10 bar parameter range. Main task of this work is to model pressure sensor using commercial mathematical modelling programs ANSYS and ANSYS CFX, optimize model parameters to fit experimental data and to evaluate role of different physical effects, especially role of heat and mass transfer. 2. Modeled equipment The equipment consists of two symmetric loud speaker shaped membranes which are welded together in the outer part W. Figure 1 shows 2D axisymmetric model geometry. Approximate diameter of whole system is 77 mm. It is possible to pump gas in cavities CT and CB. There is vacuum in cavity V. When no gas is pumped, the two membranes MT and MB just touch in a contact surface C, no large contact pressure occurs. Heating at point HT causes a local rise in temperature. With its supporting membrane MT made of material with low thermal conductivity a significant temperature gradient to the Fig. 1. Geometry of axisymmetric model. CT and CB – top and bottom cavity which are filled with gas, MT and MB – top and bottom membrane, V – vacuum cavity, C – contact surface, W – welded part, HT and HB – points between which temperature difference is measured, HT is heated