The existing methods to study mechanical gas face seals are computationally intensive or have limitations due to linearized description of the gas film coefficients. This dissertation develops modeling, estimation and control methods for mechanical gas face seal systems that overcome the disadvantages of the existing methods. In Paper I, an approach based on Proper Orthogonal Decomposition and Galerkin projection is presented for developing low-order nonlinear models of the gas film pressure in mechanical gas face seals. In Paper II, a method using reduced-order Kalman filters is developed to estimate the thin gas film axial force and moments in real-time. In Paper III, a control methodology that utilizes a robust Model Reference Adaptive Control technique is presented to regulate the dynamic behavior of mechanical gas face seal systems. The modeling, estimation and control methods developed in Papers I, II and III, respectively, are applied to a coned mechanical gas face seal in a flexibly mounted stator configuration without rotor runout or initial stator misalignment. The reduced-order gas film models are shown to be computationally efficient and valid within a wide range of operating conditions. The estimators are shown to approximate the gas film axial force and moments successfully for different forcing functions over a wide range of compressibility numbers. The controllers are able to stabilize the axial clearance and tilts effectively. The control methodology developed in Paper III is applied in Paper IV to regulate the dynamic behavior of a similar seal with rotor runout and initial stator misalignment. Simulation results show that the controllers effectively stabilize the axial clearance and control the tilts to track reference model outputs.
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