Rotordynamics of Gas-Lubricated Journal Bearing Systems by Krzysztof Czolczynski

By Krzysztof Czolczynski

Gas bearings were used to help rotating elements in quite a lot of purposes - from magnetic recording heads in computing device disk drives to gyroscopes and targeted desktop instruments. the good thing about fuel bearings is the very low viscosity of air in comparison to that of such a lot oils utilized in lubrication. consequently, not just is there less frictional warmth to fritter away, however the bearing is still almost isothermal. gasoline bearings can therefore help rotors spinning at a lot larger rotational velocities than these lubricated with drinks. This e-book discusses versions for the habit of fuel bearings, quite of the features affecting the steadiness of the procedure. It starts with a dialogue of the mathematical versions, settling on the stiffness and damping coefficients, and describing the habit of the types in volatile areas. It then turns to use those effects to bearings: static features and balance of assorted rotor platforms and an in depth dialogue of air rings.

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Extra info for Rotordynamics of Gas-Lubricated Journal Bearing Systems

Example text

With the actual value of H, the Reynold's equation and the equations describing the mass flow through the feeding system are solved. It provides a new pressure distribution in the gap between the shaft and the bushing. 3. The new value of the internal force can be estimated as the integral of the pressure distribution. 4. All the values: displacement and velocity from step 1, pressure distribution from step 2, and internal force from step 3, make new initial conditions. With this set of values the procedure returns to step 1 to calculate what will happen in the time interval M- 2M.

Twenty-five coefficients of this polynomial have been determined on the basis of the values of the function being approximated in 25 points lying in the neighborhood of the approximation point (A, v). 11. The values of the function being approximated are known in the points of the coordinates (A, v), which assume the values A_2, AI> Ao, AI> A2 and V_2, V_I> Yo, VI, V2 parallel to each other. 6 • 1denIIf. 12. Sample of the trigonometric approximation, C II , A = 12, selfacting bearing. 46) 5dv 5dv (v-v o)] U~(V-vo)] 5dv }.

These sets of equations can be solved using the method of minimalization of the least square cost functions. The author tried to use this method to estimate eight coefficients of the investigated bearing; he failed. 3. 3, which shows,that the results are far from expected. There is a simple explanation for this: Although the bearing is a nonlinear system, the time series of X, y, x, and yare almost harmonic, so they depend one another and the estimated values of the coefficients are purely accidental.

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