Analysis of end-face seals by FEM

The end face-seals joint simultaneously the function of seal, bearing and heat exchanger. In order to improve the design of end-face seals the analysis of this type of joint by means of finite element method, was developed. The temperature distribution is indispensable to the analysis of displacement and stress in this type of face seal. In this work the values of temperature and stress in end-face seals were calculated. The numerical results were confirmed by measurements in the laboratory. Introduction In technical applications of the measurements of temperature in many devices are possible only in selected points. The problems of determining of temperature distribution are very important particularly in metal-ceramic joints, which we can meet in end-face seals. This problem is often encountered in various pumps of used in car and power industry. The subject of analysis is the end-face seal, which is numbered among the second loading group in the range of working medium pressure (included in the range of 0,1 to 1,0 MPa) as well as the third loading group taking into consideration the average rotational speed of one of rings [1], [2]. When determining the pressure and rotational speed (it can be done without any problem) the determination of distribution of temperatures in a free (any) element of seal encounters significant difficulties because the temperature measurement is possible to carry out only in selected points. So it is impossible to determine distribution of temperatures in seal, especially in a slide pair. The aim of our work is to determine the temperature and strain distribution in end-face seals in order to avoid a leakage in this type of joint. The problem of determining of temperature distribution is essential for ceramic-metals joints occurring in end-face seals. As a result of face seals, which are constructed on the basis of different materials with different mechanical and thermal properties, a thermal stress can appear. Regarding the increasing accuracy of numerical simulations, we performed special data base of materials parameters. This data can draw proper material data from tensile curves stored by Instron tensile machine and automatically convert to the integrated input FEM method. Features of the numerical model The end-face seal can be performed as an axisymmetrical problem. In this work, the numerical model of end-face seal is discretized by finite elements [3]. The model has over 3800-node, 3560 continuum elements (plane 42, 13, contact 48) and 3793 degrees of freedom were employed. The distribution of temperature and stress were modeled by a thermal solid element and coupled-field solid element taken from the Ansys System FE. Fig. 1 shows a model of testing stand chamber with the development seal. Fig.1 Seal elements development in the testing stand chambe r – a calculation model. • K, W, O, A, C, E denote components of elements of seal; • B, D, F, G, H denote components of elements of testing stand chamber. 1 J. Juraszek, University Bielsko-Biała, Willowa 2, 43-309 Bielsko-Biała, Poland. (Reviewed, revised version received August, 14 2002)