Externally-pressurized Gas Research Articles

Static Performance Analysis of Orifice Compensated Externally Pressurized Gas Spherical Bearing Based on FEM

In order to optimize static performance of a new orifices compensated externally pressurized gas spherical bearing, the paper presents a theoretical study using finite element method (FEM). Galerkin weighted residual method is applied to reduce the order of derivatives of the transformed Reynolds equation. On the basis of theoretical analysis, the influence of supplying pressure and geometrical parameters to radial load carrying capacity and stiffness was analyzed. As a result, the reasonable range of the bearing’s parameters was proposed.

Stability research of externally pressurized gas bearings for the cryogenic expansion turbine

This Paper describes the research results of some externally pressurized (EP) gas bearings for the medium-pressure cryogenic expansion turbine. The experimental EP bearings consist of rigidlymounted and flexibly-mounted types, which include various configurations with radial and tangential feed-holes. The effects of some factors on the instability onset speed, n c have been investigated and the n c-2Cr characteristic curves have been obtained. A comparison between the n c-2 Cr curves of different configurations of EP gas bearings shows that three configurations exist which possess not only higher stability, but also excellent n c-2 Cr characteristics. Recently, they have been successfully applied to the cryogenic expansion turbines.

Dynamic Properties of Externally-Pressurized Gas Journal Bearings with Circular Slot Restrictors

The externally-pressurized gas journal bearings with circular slot restrictors are investigated theoretically and experimentally to determine their dynamic properties. The theoretical analyses are presented for a single-row admission bearing and a double-row admission one. respectively, by using Reynolds equations in which inertial forces of a gas film are considered. The accuracy of the theoretical method is consequently shown that the present theoretical method can accurately predict the dynamic properties of a gas journal bearing with a circular slot restrictor.

Dynamic Properties of Externally-Pressurized Gas Journal Bearings with Circular Slot Restrictors

Dynamic Properties of Externally-Pressurized Gas Journal Bearings with Circular Slot Restrictors

A Study of the Stability of an Externally-Pressurized Gas-Lubricated Thrust Bearing With a Flexible Damped Support

Externally-pressurized gas bearings are prone to a dynamic instability known as pneumatic hammer. This paper examines the possibility of using a flexible damped bearing support to suppress the instability. A circular thrust bearing having a central feed hole and pocket is employed in the feasibility study. The linearized gas film dynamic coefficients are derived using an adaptation of an existing solution to Reynolds equation for a long rectangular bearing. Only stability of the equilibrium position is considered. Results obtained for a support having a stiffness comparable to the stiffness of the gas film show that damping in the support can substantially improve stability.

A Simplified Method for the Design of Externally Pressurized Gas Lubricated Thrust Bearings

A simplified procedure has been developed for the performance estimation of externally-pressurized gas lubricated thrust bearings. Both orifice-compensated and inherently-compensated bearings may be treated. Empirical correlations for the entry compensation pressure drop are combined with numerically determined flow and load factors for the clearance space flow. The analytical predictions are compared with empirical studies indicating satisfactory agreement for most design purposes.

Description and Performance of the Saturn Launch Vehicle's Navigation, Guidance, and Control System

A review of the navigation, guidance, and control system of the Saturn launch vehicle includes the system analysis and design, signal flow diagrams, redundancy, and self-checking features used to obtain extreme reliability for crew safety.The iterative path adaptive guidance mode, featuring flight path optimization, is explained and presented in its computational form. Following the analytical considerations, the main guidance and control components are described. The navigation and control information is obtained inertinlly by a gyro-servo-stabilized, three-gimbal platform system with three mutually orthogonal pendulous-integrating gyro accelerometers; the single-degree-of-freedom gyros as well as the accelerometers use externally-pressurized gas bearings. Rate gyroscopes provide attitude staoilization; some vehicle configurations require additional accelerometer control to reduce wind loads. The digital computer system serves as the computation, central data, and onboard programing center, which ties in with the ground computer system during the prelaunch checkout of the overall system. The control signals are combined, shaped, attenuated, and amplified by an analog type control computer for engine actuator control.Results obtained in recent launchings of Saturn V vehicles are presented to confirm the adequacy of the navigation, guidance, and control system and its overall performance even under extreme flight perturbations.

Design criteria for externally-pressurized gas bearings for operation at high temperatures and high speeds : P. Lewis, M. Eusepi and J. L. Morris, ASLE Trans., 9 (1966) 402–410

Design criteria for externally-pressurized gas bearings for operation at high temperatures and high speeds : P. Lewis, M. Eusepi and J. L. Morris, ASLE Trans., 9 (1966) 402–410

The effect of dry and fluid lubrication on instrument, ball-bearing torques at high speed : H. H. Mabie, Lubrication Eng., 21 (6) (1965) 242–249; 21 figs., 1 table

A review of the navigation, guidance, and control system of the Saturn launch vehicle includes the system analysis and design, signal flow diagrams, redundancy, and self-checking features used to obtain extreme reliability for crew safety.The iterative path adaptive guidance mode, featuring flight path optimization, is explained and presented in its computational form. Following the analytical considerations, the main guidance and control components are described. The navigation and control information is obtained inertinlly by a gyro-servo-stabilized, three-gimbal platform system with three mutually orthogonal pendulous-integrating gyro accelerometers; the single-degree-of-freedom gyros as well as the accelerometers use externally-pressurized gas bearings. Rate gyroscopes provide attitude staoilization; some vehicle configurations require additional accelerometer control to reduce wind loads. The digital computer system serves as the computation, central data, and onboard programing center, which ties in with the ground computer system during the prelaunch checkout of the overall system. The control signals are combined, shaped, attenuated, and amplified by an analog type control computer for engine actuator control.Results obtained in recent launchings of Saturn V vehicles are presented to confirm the adequacy of the navigation, guidance, and control system and its overall performance even under extreme flight perturbations.

Gyroscope research at the Franklin Institute

A review of the navigation, guidance, and control system of the Saturn launch vehicle includes the system analysis and design, signal flow diagrams, redundancy, and self-checking features used to obtain extreme reliability for crew safety.The iterative path adaptive guidance mode, featuring flight path optimization, is explained and presented in its computational form. Following the analytical considerations, the main guidance and control components are described. The navigation and control information is obtained inertinlly by a gyro-servo-stabilized, three-gimbal platform system with three mutually orthogonal pendulous-integrating gyro accelerometers; the single-degree-of-freedom gyros as well as the accelerometers use externally-pressurized gas bearings. Rate gyroscopes provide attitude staoilization; some vehicle configurations require additional accelerometer control to reduce wind loads. The digital computer system serves as the computation, central data, and onboard programing center, which ties in with the ground computer system during the prelaunch checkout of the overall system. The control signals are combined, shaped, attenuated, and amplified by an analog type control computer for engine actuator control.Results obtained in recent launchings of Saturn V vehicles are presented to confirm the adequacy of the navigation, guidance, and control system and its overall performance even under extreme flight perturbations.