Performance and Stability of a Hybrid Spherical Gas Gyrobearing

1991 ◽  
Vol 113 (3) ◽  
pp. 458-463 ◽  
Author(s):  
N. M. Sela ◽  
J. J. Blech
Keyword(s):  
Equilibrium Point ◽  
Dynamic Stability ◽  
Flow Rate ◽  
Gas Flow ◽  
Reynolds Equation ◽  
Load Capacity ◽  
Equations Of Motion ◽  
Gas Flow Rate ◽  
Small Perturbations ◽  
Static Performance

A new spherical Gas Gyrobearing configuration is presented. The static performance is evaluated for general eccentricity, and data is presented for load capacity, gas flow rate and error torque, over a range of eccentricities and gas feed pressures. The dynamic stability of the rotor about an equilibrium point, assuming small perturbations, is analyzed using the step-jump method. Finally, a nonlinear path simulation was performed, by simultaneously solving the Reynolds equation and the rotor’s equations of motion.

Static performance of the aerostatic journal bearing with grooves

2019 ◽  
Vol 234 (7) ◽  
pp. 1114-1130
Author(s):  
Xinglong Chen ◽  
James K Mills ◽  
Gang Bao
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Journal Bearing ◽  
Load Capacity ◽  
Groove Depth ◽  
Load Force ◽  
Orifice Diameter ◽  
Geometrical Parameters ◽  
Gas Flow Rate ◽  
Static Performance

Aerostatic bearings are widely employed in precision machines due to their properties of low friction, low heat conduction, and long-life operation. In this work, static performance of the journal bearing with rectangular grooves is investigated numerically. The effect of geometrical parameters such as axial groove length [Formula: see text], circumferential groove length [Formula: see text], orifice diameter df, groove depth gh, misalignment angles [Formula: see text] and [Formula: see text] on the load capacity [Formula: see text], stiffness [Formula: see text], and gas flow rate [Formula: see text] are analyzed systematically. The resistance network method (RNM) is utilized to solve the Reynolds equation required in the analysis. Performance parameters including pressure distribution P, load force [Formula: see text], stiffness [Formula: see text], and gas flow rate [Formula: see text] are examined in the simulations. It is revealed from the simulations that the proper value of axial groove length [Formula: see text] to obtain a better static performance varies from 1/8 to 1/2 when df varies between 0.11 and 0.29 mm, respectively. Therefore, a larger load force and stiffness can be obtained if [Formula: see text] is chosen to be 1/4, when diameter of the bearing orifice df equals 0.17 mm. It is also suggested that [Formula: see text] be chosen from the range of 1/6 and 1/3 to obtain a better static performance and a smaller gas flow rate. [Formula: see text] decreases with an increase in df when [Formula: see text] is set to be 1/8. However, the load force [Formula: see text] increases with an increase in df when [Formula: see text] varies from 3/8 to 1/2. [Formula: see text] has a significant influence on the changes of [Formula: see text] with df when [Formula: see text] is set to be constant. Therefore, df should be selected according to [Formula: see text] for an optimal design. The increase of misalignment angle [Formula: see text] leads to an increase in the load force [Formula: see text]. [Formula: see text] has little influence on the load force [Formula: see text]. Misalignment angles [Formula: see text] and [Formula: see text] have little influence on stiffness [Formula: see text] and gas flow rate [Formula: see text]. Therefore, it is preferable if [Formula: see text] is larger than 0 rad.

Performance of Hydrostatic Spherical Gas Gyro Bearings

1976 ◽  
Vol 98 (1) ◽  
pp. 111-116 ◽  
Author(s):  
A. Gu ◽  
L. Cziglenyi
Keyword(s):  
Numerical Solution ◽  
Flow Rate ◽  
Gas Flow ◽  
Load Capacity ◽  
Performance Data ◽  
Drag Torque ◽  
Fixed Bearing ◽  
Gas Flow Rate

Analysis and method of numerical solution for evaluating the performance of hydrostatic spherical gas gyro bearings at any gimbal angle and at any eccentricity have been developed. Performance data on load capacity, gas flow rate, drag torque, and error torque over some ranges of gimbal angle and eccentricity are presented. Comparison has been made between the equatorially vented and nonvented bearings of fixed bearing angles.

SCIENTIFIC AND ENGINEERING PRINCIPLES OF EFFICIENT FUEL USE AND ENVIRONMENTALLY FRIENDLY GAS COMBUSTION IN STOVE PLATES. PART 1. MODERN STATE-OF-THE-ART AND DIRECTIONS FOR IMPROVEMENT THE GAS BURNING IN DOMESTIC GAS COOKERS

2017 ◽  
pp. 3-18 ◽  
Author(s):  
B.S. Soroka ◽  
V.V. Horupa
Keyword(s):  
Natural Gas ◽  
Flow Rate ◽  
Gas Flow ◽  
Renewable Energy Sources ◽  
Combustion Process ◽  
Orifice Diameter ◽  
Firing Process ◽  
Gas Flow Rate ◽  
Gas Combustion ◽  
Gas Stoves

Natural gas NG consumption in industry and energy of Ukraine, in recent years falls down as a result of the crisis in the country’s economy, to a certain extent due to the introduction of renewable energy sources along with alternative technologies, while in the utility sector the consumption of fuel gas flow rate enhancing because of an increase the number of consumers. The natural gas is mostly using by domestic purpose for heating of premises and for cooking. These items of the gas utilization in Ukraine are already exceeding the NG consumption in industry. Cooking is proceeding directly in the living quarters, those usually do not meet the requirements of the Ukrainian norms DBN for the ventilation procedures. NG use in household gas stoves is of great importance from the standpoint of controlling the emissions of harmful components of combustion products along with maintenance the satisfactory energy efficiency characteristics of NG using. The main environment pollutants when burning the natural gas in gas stoves are including the nitrogen oxides NOx (to a greater extent — highly toxic NO2 component), carbon oxide CO, formaldehyde CH2O as well as hydrocarbons (unburned UHC and polyaromatic PAH). An overview of environmental documents to control CO and NOx emissions in comparison with the proper norms by USA, EU, Russian Federation, Australia and China, has been completed. The modern designs of the burners for gas stoves are considered along with defining the main characteristics: heat power, the natural gas flow rate, diameter of gas orifice, diameter and spacing the firing openings and other parameters. The modern physical and chemical principles of gas combustion by means of atmospheric ejection burners of gas cookers have been analyzed from the standpoints of combustion process stabilization and of ensuring the stability of flares. Among the factors of the firing process destabilization within the framework of analysis above mentioned, the following forms of unstable combustion/flame unstabilities have been considered: flashback, blow out or flame lifting, and the appearance of flame yellow tips. Bibl. 37, Fig. 11, Tab. 7.

On the Influence of Fluctuating Flow Rate Upon the Performance and Behaviour of Isothermal Reacting Systems

1998 ◽  
Vol 63 (6) ◽  
pp. 881-898
Author(s):  
Otakar Trnka ◽  
Miloslav Hartman
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Fluidized Bed Reactor ◽  
Computational Techniques ◽  
Continuous Stirred Tank Reactor ◽  
Gas Flow Rate ◽  
Solid Reaction ◽  
Continuous Stirred Tank ◽  
And Performance ◽  
Reacting Systems

Three simple computational techniques are proposed and employed to demonstrate the effect of fluctuating flow rate of feed on the behaviour and performance of an isothermal, continuous stirred tank reactor (CSTR). A fluidized bed reactor (FBR), in which a non-catalytic gas-solid reaction occurs, is also considered. The influence of amplitude and frequency of gas flow rate fluctuations on reactant concentrations at the exit of the CSTR is shown in four different situations.

scholarly journals Investigation on influences of loose gas on gas-solid flows in a circulating fluidized bed (CFB) reactor using full-loop numerical simulation

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Pengju Huo ◽  
Xiaohong Li ◽  
Yang Liu ◽  
Haiying Qi
Keyword(s):  
Numerical Simulation ◽  
Flow Rate ◽  
Gas Flow ◽  
Circulating Fluidized Bed ◽  
Separation Efficiency ◽  
Circulation Rate ◽  
Solid Mass ◽  
Gas Flow Rate ◽  
Gas Leakage ◽  
Mass Circulation

AbstractThe influences of loose gas on gas-solid flows in a large-scale circulating fluidized bed (CFB) gasification reactor were investigated using full-loop numerical simulation. The two-fluid model was coupled with the QC-energy minimization in multi-scale theory (EMMS) gas-solid drag model to simulate the fluidization in the CFB reactor. Effects of the loose gas flow rate, Q, on the solid mass circulation rate and the cyclone separation efficiency were analyzed. The study found different effects depending on Q: First, the particles in the loop seal and the standpipe tended to become more densely packed with decreasing loose gas flow rate, leading to the reduction in the overall circulation rate. The minimum Q that can affect the solid mass circulation rate is about 2.5% of the fluidized gas flow rate. Second, the sealing gas capability of the particles is enhanced as the loose gas flow rate decreases, which reduces the gas leakage into the cyclones and improves their separation efficiency. The best loose gas flow rates are equal to 2.5% of the fluidized gas flow rate at the various supply positions. In addition, the cyclone separation efficiency is correlated with the gas leakage to predict the separation efficiency during industrial operation.

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