Experimental validation of characteristic diagram- parameterization for environment-induced thermal interactions on machine tools in a climate chamber

Thermal gradients created by environmental influences on machine tools cause considerable non-linear thermo-elastic deformations whether the machine is in operation or in idle mode. When a machine tool is subjected to changes in environmental influences such as ambient air temperature, velocity or direction, then flow (CFD) simulations are necessary to effectively quantify the thermal behavior between the machine tool surface and the surrounding air. The conventional two-step simulation procedure consisting of coupled CFD and thermo-elastic simulation is highly time-consuming especially when complex geometries are considered. Decoupling of CFD and thermo-elastic simulation can be achieved by introducing a Clustering Algorithm (CA) and Characteristic Diagrams (CDs) within the simulation workflow. Using training data obtained from a limited number of CFD simulations, the CDs can predict the heat transfer coefficients (HTCs) based on the parameterized environmental influences. This paper attempts to validate the experimental temperature and displacement readings obtained at selected positions on a machine tool using a wide range of metrological equipment such thermography camera, temperature and displacement sensors with the decoupling approach based on parameterized CDs. For investigation, the machine tool is positioned in a climate chamber, which facilitates the variation of environmental influences such as ambient temperature, flow velocity and flow direction. Initially, a precise coupled simulation model is created which is later on converted to a decoupled system using parameterized CDs.