P3.3 - Determination of the Dynamic Behavior of High-Speed Temperature Sensors

SENSOR+TEST Conferences 2011
2011-06-07 - 2011-06-09
Proceedings SENSOR 2011
P3 - Temperature / Humidity
S. Augustin, T. Fröhlich, H. Mammen - Technische Universität Ilmenau (Germany)
726 - 731


Currently at manufacturers of thermocouples, development is being continued on thermometers especially suited for applications in the automobile and aircraft industries. These thermometers must very quickly react to sometimes very large temperature jumps, which is where emphasis in design optimisation with respect to small time-percentage characteristics has been placed. These sensors are applied in areas with large temperature gradients and high flow velocities. In order to optimise the dynamic and static parameters (response times, thermal conduction errors), the Department of Process Measurement Technology in cooperation with Temperaturmesstechnik Geraberg GmbH and other manufactures is constructing a testing apparatus, in which the sensors characteristics can be determined as close as possible to standard conditions. In parallel, numerical calculation of the static and dynamic behaviour can be done for various possible designs, taking the assembly points into account with the help of the finite element method.

For these calculations the temperature dependence of the material properties (thermal conductance, thermal capacity, coefficient of thermal expansion) should be included in the model computations. The FEM simulations are therefore not only non-steadystate but also nonlinear. Consideration of the temperature dependence of the material characteristics is necessary because the previous knowledge gained experimentally show that the time behaviour of the sensors is significantly different for various step heights and directions. When exactly determining the corresponding sensor parameters, the exact description of the inner sensor design as well as the points of assembly play important roles due to the large expected flow velocities and the small resistance to heat transfer arising from them. This is confirmed by initial numerical calculations for simple sensor designs done in the Department.