Research on Fluctuating Forces Occurred in Components of Reciprocating Hydrogen Compressors

2012 ◽  
Author(s):  
Yoshifumi Mori ◽  
Takashi Saito ◽  
Takehisa Aoki ◽  
Katsuhide Fujita
Keyword(s):  
Degrees Of Freedom ◽  
Beam Theory ◽  
Contact Theory ◽  
Model Parameters ◽  
Petrochemical Plant ◽  
Term Operation ◽  
Proposed Model ◽  
Rigid Body Model ◽  
System 1

This paper treats dynamic analysis about reciprocating compressors used in a petroleum refining plant and a petrochemical plant. In order to clarify the cause of damage occurred as a result of long-term operation, we investigated the effects of deterioration around the connecting parts and the sliding parts on the dynamics of the system. Introducing the rigid body model with eleven degrees of freedom, we have determined the model parameters based on beam theory and the Hertz contact theory. By comparison with experimental results, we showed validity of the proposed model. Thus, changes in the characteristics of the middle spring piston rod were found to be a major impact on the dynamics of the system [1].

scholarly journals Optimization Model for the Long-Term Operation of an Interprovincial Hydropower Plant Incorporating Peak Shaving Demands

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4804
Author(s):  
Rui Cao ◽  
Jianjian Shen ◽  
Chuntian Cheng ◽  
Jian Wang
Keyword(s):  
Power Generation ◽  
Optimization Model ◽  
Hydropower Plant ◽  
Mixed Integer ◽  
Short Term ◽  
Long Distance ◽  
Peak Shaving ◽  
Term Operation ◽  
Proposed Model

The increasing peak-to-valley load difference in China pose a challenge to long-distance and large-capacity hydropower transmission via high-voltage direct current (HVDC) lines. Considering the peak shaving demands of load centers, an optimization model that maximizes the expected power generation revenue is proposed here for the long-term operation of an interprovincial hydropower plant. A simulation-based method was utilized to explore the relationships between long-term power generation and short-term peak shaving revenue in the model. This method generated representative daily load scenarios via cluster analysis and approximated the real-time electricity price of each load profile with the time-of-use price strategy. A mixed-integer linear programming model with HVDC transmission constraints was then established to obtain moving average (MA) price curves that bridged two time-coupled operations. The MA price curves were finally incorporated into the long-term optimization model to determine monthly generation schedules, and the inflow uncertainty was addressed by discretized inflow scenarios. The proposed model was evaluated based on the operation of the Xiluodu hydropower system in China during the drawdown season. The results revealed a trade-off between long-term energy production and short-term peak shaving revenue, and they demonstrated the revenue potential of interprovincial hydropower transmission while meeting peak shaving demands. A comparison with other long-term optimization methods demonstrated the effectiveness and reliability of the proposed model in maximizing power generation revenue.

Dynamic Stress Analysis of Exposed Pipes Subjected to Moving In-Line Inspection Tool

2020 ◽  
Author(s):  
Hamid Mostaghimi ◽  
Mohsen Hassani ◽  
Deli Yu ◽  
Ron Hugo ◽  
Simon Park
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Stress ◽  
Equations Of Motion ◽  
Excitation Frequency ◽  
Beam Theory ◽  
Assessment Method ◽  
Integrity Assessment ◽  
Defect Assessment ◽  
Proposed Model ◽  
Assessment And Monitoring

Abstract In-line inspection is a non-destructive assessment method commonly used for defect assessment and monitoring of pipelines. The passage of an ILI tool through an excavated or exposed section of a pipe during an integrity assessment can excite vibrations and exert substantial forces, stress, and deflections on the pipe due to the weight and speed of the ILI tool. When the excitation frequency due to the ILI tool movement is close to the natural frequency of the overall structure, the dynamic stress generated within the pipe can be large enough to the extent that it imposes integrity concern on the line. This research aims to study effects of the ILI tool passage through floating and partially supported pipes under a variety of boundary and loading conditions. A finite element method is used to model the pipe with moving ILI tool. The model is developed based on Timoshenko beam theory with planar degrees-of-freedom and the differential equations of motion are solved numerically to predict displacement, strain, stress, and frequency responses of the pipe. The model is further validated using a lab-scale experimental setup. The comparison of the simulation to experimental results show how the proposed model is capable of predicting pipe dynamics, effectively.

Development of a New Type of Maintenance Management System Based on Reliability for Rotating Equipments in Typical Petrochemical Plant

2015 ◽  
Author(s):  
Xiang Li ◽  
Guodong Jia ◽  
Hui Wang ◽  
Weihua Wang
Keyword(s):  
Reliability Analysis ◽  
Management System ◽  
Maintenance Management ◽  
Petrochemical Plant ◽  
Term Operation ◽  
Management Platform ◽  
Analysis Technique ◽  
Management Technology ◽  
New Type

Currently the reliability of rotating equipments in typical petrochemical plants, such as turbo machineries, centrifugal compressors, reciprocating compressors, fans, pumps, etc. plays an important role in a long-term operation of the plants. The important tasks for management technology research of rotating equipments are to build a new type of maintenance management platform and take an advantage of the reliability analysis technique for fault diagnosis and maintenance strategy optimization. In this paper, firstly, the development of maintenance management technology in China and overseas was introduced. The problems of traditional reliability analysis techniques were pointed out. Secondly, the key technologies of the new type of maintenance management system were introduced. Furthermore, the structure and work process of the new type of maintenance management system were proposed. Finally, the key contents and functions of this system were given.

scholarly journals A 3-D Pseudo-Rigid Body Model for Rectangular Cantilever Beams With an Arbitrary Force End-Load

2014 ◽  
Author(s):  
Jairo Chimento ◽  
Craig Lusk ◽  
Ahmad Alqasimi
Keyword(s):  
Rigid Body ◽  
Cross Sections ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Neutral Axis ◽  
Spatial Behavior ◽  
Model Parameters ◽  
Cantilever Beams ◽  
Body Model ◽  
Rigid Body Model

This paper presents the first three-dimensional pseudo-rigid body model (3-D PRBM) for straight cantilever beams with rectangular cross sections and spatial motion. Numerical integration of a system of differential equations yields approximate displacement and orientation of the beam’s neutral axis at the free-end, and curvatures of the neutral axis at the fixed-end. This data was used to develop the 3-D PRBM which consists of two torsional springs connecting two rigid links for a total of 2 degrees of freedom (DOF). The 3-D PRBM parameters that are comparable with existing 2-D model parameters are characteristic radius factor (means: γ = 0.8322), bending stiffness coefficient (means: KΘ = 2.5167) and parametric angle coefficient (means: cΘ = 1.2501). New parameters are introduced in the model in order to capture the spatial behavior of the deflected beam including two parametric angle coefficients (means: cΨ = 1.0714; cΦ = 1.0087).

Stability Analysis of Composite Shafts Considering Internal Damping and Coupling Effect

2020 ◽  
Vol 20 (11) ◽  
pp. 2050118
Author(s):  
Kwangchol Ri ◽  
Poknam Han ◽  
Inchol Kim ◽  
Wonchol Kim ◽  
Hyonbok Cha
Keyword(s):  
Degrees Of Freedom ◽  
Coupling Effect ◽  
Lagrange Equation ◽  
Nodal Point ◽  
Single Layer ◽  
Beam Theory ◽  
Weak Form ◽  
Internal Damping ◽  
Proposed Model ◽  
Equivalent Modulus

A mathematical model is proposed to analyze the stability of composite shafts, considering the internal damping, transverse shear deformation and Poisson’s coupling effect at the same time. The strain–displacement relations are described using the Timoshenko beam theory, and the strain energy and kinetic energy are expressed using the weak form quadrature element method (QEM), for which each nodal point has 4 degrees of freedom. Then, the motion equation of the system is established using the Lagrange equation. The instability thresholds of the composite shaft are determined using the proposed model. The results were compared with those calculated by the equivalent modulus beam theory (EMBT), equivalent single layer theory (ESLT) and simplified homogenized beam theory (SHBT). Good agreement has been achieved. Therefore, the proposed model can be effectively used for the dynamic analysis of composite shafts.

In-Plane Flexible Ring Tire Model—Part 1: Modeling and Parameter Identification

2018 ◽  
Vol 46 (3) ◽  
pp. 174-219 ◽  
Author(s):  
Bin Li ◽  
Xiaobo Yang ◽  
James Yang ◽  
Yunqing Zhang ◽  
Zeyu Ma
Keyword(s):  
Static Load ◽  
Model Parameters ◽  
Tire Model ◽  
Test Results ◽  
Lumped Mass ◽  
Virtual Test ◽  
Proposed Model ◽  
Particle Swarm Method ◽  
Vehicle Dynamic Simulation ◽  
Flexible Ring

ABSTRACT The tire model is essential for accurate and efficient vehicle dynamic simulation. In this article, an in-plane flexible ring tire model is proposed, in which the tire is composed of a rigid rim, a number of discretized lumped mass belt points, and numerous massless tread blocks attached on the belt. One set of tire model parameters is identified by approaching the predicted results with ADAMS® FTire virtual test results for one particular cleat test through the particle swarm method using MATLAB®. Based on the identified parameters, the tire model is further validated by comparing the predicted results with FTire for the static load-deflection tests and other cleat tests. Finally, several important aspects regarding the proposed model are discussed.

Sign in / Sign up

Export Citation Format

Share Document