Analysis of the Design of Henry Muncaster’s Two-Cylinder Compound Vertical Steam Engine with Speed Control

Abstract

This article offers an analysis, from the mechanical engineering viewpoint, of an invention by Henry Muncaster from 1912: the two-cylinder compound vertical steam engine with speed control. This is an invention with a large number of components (106) that was used as an engine in boats and railways. The ultimate objective of this investigation was to determine the operating conditions (maximum pressures of water vapor in the admission of high- and low-pressure cylinders) according to the criteria of resistance of materials since there is no information about this. Therefore, two critical operating conditions were simulated that resemble the start-up of the machine (flywheel locked as the most unfavorable situation) in order to determine those operating conditions that ensure both its safety and optimal operation. For this, a static linear analysis based on the finite element method (FEM) of the 3D CAD model was carried out under real operating conditions, according to the criteria of resistance of materials, using the Autodesk Inventor Nastran 2023 software. The results of the static linear analysis (von Mises stress, displacement and safety factor) confirmed the maximum values of the vapor pressure in the admission of the cylinders: 0.3 MPa on the high-pressure piston plunger and 0.15 MPa on the low-pressure piston plunger.