scholarly journals Dynamic Model for Axial Motion of Horizontal Pelton Turbine and Validation in Actual Failure Case

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
C. G. Rodriguez ◽  
D. Zambrano ◽  
S. Reyes ◽  
J. Tapia ◽  
M. Egusquiza ◽  
...  
Keyword(s):  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Magnetic Force ◽  
Operating Conditions ◽  
Axial Position ◽  
Axial Motion ◽  
Nonlinear Dynamic Model ◽  
Pelton Turbine ◽  
Axial Forces ◽  
The Difference

Pelton turbines are important machines for power generation from a renewable energy source such as water. For power rates below 20 MW, the rotor of Pelton turbines is usually in horizontal position. Considering ideal mounting and operating conditions, there are no axial forces acting on the rotor. In practice, there is an hydraulic force due to the difference between nozzle centerline and bucket centerline, and there is a magnetic force due to the difference between axial position of stator and rotor magnetic field centers. These forces are supported by bearings. In this article, a nonlinear dynamic model considering these axial forces and bearings behavior is presented and solved for two different actual Pelton turbines. The nonlinear dynamic model allows determining and evaluating the source of axial motion and therefore provides valuable information in order to reduce it when the axial displacement is high enough to produce damage.

Nonlinear Dynamic Model of a Two-Stage Pressure Relief Valve for Designers

2001 ◽  
Vol 124 (1) ◽  
pp. 62-66 ◽  
Author(s):  
Pei-Sun Zung ◽  
Ming-Hwei Perng
Keyword(s):  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Dynamic Models ◽  
Operating Conditions ◽  
Model Parameters ◽  
Nonlinear Dynamic Model ◽  
Relief Valve ◽  
Two Stage ◽  
Pressure Relief ◽  
Wide Range

This paper presents a handy nonlinear dynamic model for the design of a two stage pilot pressure relief servo-valve. Previous surveys indicate that the performance of existing control valves has been limited by the lack of an accurate dynamic model. However, most of the existing dynamic models of pressure relief valves are developed for the selection of a suitable valve for a hydraulic system, and assume model parameters which are not directly controllable during the manufacturing process. As a result, such models are less useful for a manufacturer eager to improve the performance of a pressure valve. In contrast, model parameters in the present approach have been limited to dimensions measurable from the blue prints of the valve such that a specific design can be evaluated by simulation before actually manufacturing the valve. Moreover, the resultant model shows excellent agreement with experiments in a wide range of operating conditions.

Analysis of Tourism Ecology Capacity Based on the Nonlinear Dynamic Model

2009 ◽  
Vol 11 (2) ◽  
pp. 163-168
Author(s):  
Long LV ◽  
Zhenfang HUANG ◽  
Jiang WU
Keyword(s):  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Model

scholarly journals Rattle dynamics of noncircular face gear under multifrequency parametric excitation

2021 ◽  
Vol 12 (1) ◽  
pp. 361-373
Author(s):  
Dawei Liu ◽  
Zhenzhen Lv ◽  
Guohao Zhao
Keyword(s):  
Dynamic Model ◽  
Parametric Excitation ◽  
Nonlinear Dynamic ◽  
Velocity Ratio ◽  
Harmonic Balance Method ◽  
Transmission Error ◽  
Dynamic Responses ◽  
Discrete Fourier Transformation ◽  
Nonlinear Dynamic Model ◽  
Face Gear

Abstract. A noncircular face gear (NFG) conjugated with a pinion is a new type of face gear which can transmit variable velocity ratio and in which two time-varying excitations exist, namely the meshing stiffness excitation and instantaneous center excitation. Considering the tooth backlash, static transmission error and multifrequency parametric excitation, a nonlinear dynamic model of the NFG pair is presented. Based on the harmonic balance method and discrete Fourier transformation, a semi-analytic approach for the nonlinear dynamic model is given to analyze the dynamic behaviors of the NFG. Results demonstrate that, with increase in the eccentric ratio, input velocity and error amplitude, the NFG will undergo a non-rattle, unilateral rattle and bilateral rattle state in succession, and a jump phenomenon will appear in the dynamic responses when the rattle state of the gears is transformed from unilateral rattle to bilateral rattle.

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