Numerical Investigation of the Effect of Cylinder Head Torque on Gas Leakage in Hermetic Compressors

Today, while creating compressor designs, energy efficiency and every detail related to it are given importance. In this sense, it’s critical to ensure maximum sealing in possible leakage areas. One of the most important reasons for leakages; the deformations that occur during torquing process required for the assembly of the components. Body, valve plate, cylinder head, muffler and gaskets form a sandwich structure after assembly. Although gaskets are placed between the components in structure, sufficient pressure isn’t provided in some areas on the gaskets as a result of deformations and leaks occur. Also, thermal loads can cause extra deformations and leakages. In this study, it’s aimed to calculate the deformations that will occur as a result of the assembly of the sandwich structure consisting of body, valve plate, cylinder head and gaskets and the pressures in the gaskets with the finite element model to be created. In addition, efforts were made to establish and validate a numerical methodology for detecting the possibility of leakage. Thus, structural improvements were made to reduce leakages. Firstly, the pressures formed on the gasket surfaces were observed experimentally with pressure papers. Assemblies with and without muffler were made at different torque values. The same operations were repeated in the model created by finite element method. Thus, the effect of cylinder head torque on gasket pressures was calculated both experimentally and numerically. In the last part of the study, the relationship between the experimental and numerically calculated pressure distributions and the estimated gas leakages is established.