Optimization of Self Activating Bi-Metallic Valve Using Thermo – Structural Coupled FEA

Abstract

Besides relying on electronically actuated valves, there is a need to have a mechanically actuated valve and a warning system as second layer of safety in-case of electronic malfunction. The specific process for which optimization is carried out, is the process of nitrous oxide generation from ammonium nitrate. The key challenge in the process was maintaining temperatures below 200°C, as above this temperature ammonium nitrate becomes explosive and hence safety risks are involved. The secondary objective was to maintain temperatures above 170°C, as below this temperature the reaction does not proceed. In this paper we have tried to fulfill these objectives by employing a bi-metallic valve and a warning system having bi-metallic strip which will bend at higher temperatures, thus serving our primary purpose of self-actuation. However the key constraint in determining the dimensions of the valve and the warning system is a desirable deflection of bi-metallic strip. To optimize these parameters we have employed non-linear FEA and thermo-structural coupled FEA, and this paper reflects on the process employed in achieving the same.