scholarly journals Effect of Dynamic Stress on Heavy Duty Centrifugal Pump Assembly through Fluid Structure Interaction.

2019 ◽  
Vol 8 (2S8) ◽  
pp. 1655-1659

The objective of the project is to reduce the vibration and fatigue in rotor of the centrifugal pump based on fluid structure interactions, when it rotates by the momentum of water current at different flow rate and to arrive at optimum operating conditions and perform structural analysis to determine deflection and frequency by using ANSYS 16.2.dynamic stresses are predicted at various nodal position, this would lead to suggest the method to reduce the frequency due to vibration.Computational fluid dynamics (CFD) study using Ansys 16.2 has been carried out to accomplish the objective of the work.

Author(s):  
Christian Steinbrecher ◽  
Romuald Skoda ◽  
Rudolf Schilling ◽  
Norbert Mu¨ller ◽  
Alexander Breitenbach ◽  
...  

The goal of this investigation is to contribute to the design of a centrifugal pump that can operate without bearings. This paper presents numerical studies of fluid-structure interactions on a rotating disc that can move axially unrestricted in a housing. This model mimics the gap flow between the rotor and the housing of a centrifugal pump, which stabilizes the rotor. Fluid-structure occur because of hydrodynamic forces that displace the rotor. First the effect responsible for stabilizing the rotor is described in detail. The next section presents the employed 3D Navier-Stokes Computational Fluid Dynamics (CFD) code. Special interest is given to a correct implementation of the Space-Conservation Law, where the time-dependent simulations use moving meshes. The code includes additional modules for grid generation and for calculation of the hydrodynamic forces acting on the rotor surfaces and the resulting displacement of the entire rotor. Newton’s second law is used for the coupling between hydrodynamic forces and resulting axial displacement. Results from stationary simulations are presented and compared with measurements, from the German Heart Center Munich, that show an axial displacement of the rotor results in a hydrodynamic force that pulls the rotor in the opposite direction. Finally, the results from time dependent simulations where the rotor can move unrestricted in axial position are discussed. Here, the influence of the time step is investigated, as well as the influence of geometric parameters and operating conditions.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Fu-Jun Wang ◽  
Li-Xia Qu ◽  
Ling-Yan He ◽  
Jiang-Yong Gao

The transient analysis was carried out to investigate the dynamic stress and vibration of volute casing for a large double-suction centrifugal pump by using the transient fluid-structure interaction theory. The flow pulsations at flow rate ranging from 60% to 100% of the nominal flow rate (Qd) were taken as the boundary conditions for FEM analysis of the pump volute casing structure. The results revealed that, for all operating conditions, the maximum stress located at the volute tongue region, whereas the maximum vibration displacement happened close to the shaft hole region. It was also found that the blade passing frequency and its harmonics were dominant in the variations of dynamic stress and vibration displacement. The amplitude of the dominant frequency for the maximum stress detected at 0.6Qdwas 1.14 times that atQd, lower than the related difference observed for pressure fluctuations (3.23 times). This study provides an effective method to quantify the flow-induced structural dynamic characteristics for a large-scale double-suction pump. It can be used to direct the hydraulic and structural design and stable operation, as well as fatigue life prediction for large-scale pumps.


Author(s):  
Salvador Sermeno ◽  
Eric Bideaux ◽  
Xavier Brun ◽  
Omar Ameur

Vehicle Thermal Management covers the engineering field of solutions that maintain the complete vehicle in acceptable operating conditions regarding components and fluid temperatures in an engine. The maximum efficiency rating of a Diesel engine reaches up to 45%; a vast amount of the energy produced is transformed into heat. This heat is partly rejected in the exhaust gases and partly transmitted to the engine cooling circuit. The latter can be seen in two different ways, on the one hand, cooling is necessary to regulate the fluids and component temperature to an optimum operating point for fuel efficiency and maintain engine performance. On the other hand it constitutes a loss since the coolant system actuators are engine driven (pump, fan, etc.). In order to improve the fuel efficiency of the vehicle one can reduce the losses generated by the cooling system. Ideally, the full motive force of the engine should be used for propulsion, and new and more efficient energy sources have to be explored to power the secondary systems (cooling, compressed air…). The electrification of some components in the cooling system can limit losses and improve component energy efficiency but it is not the only answer and in many cases this approach might be a limited. Recent studies have shown that by improving the control strategy of the cooling system the fuel consumption can be improved, however no real data is available since its implementation has been limited. In keeping with latter approach, this paper introduces a novel control which aims at a more efficient regulation of the cooling system operation of a Heavy Duty Truck cooling system. The main complexity in such a system remains the interactions between actuators. In this paper we propose a way to solve this using a control based on model inversion and decoupling strategy. It needs to be noted that any new approach requires the current control specifications to be modified. This enables also a better understanding of the system. However, other goals can be exploited through the use of an advanced control and the new control specifications such as a reduction of thermal shock, reduction of thermal fatigue, minimization of system overcooling (directly impacts fuel consumption but also the noise levels). Finally, the controller has been tested on a Simulation Platform using a Matlab/Simulink (Controller) and compared to the existing system control using a reference driving cycle.


Author(s):  
Scott L. Thomson ◽  
Luc Mongeau ◽  
Steven H. Frankel

Voice production is a result of the nonlinear, coupled interaction between laryngeal airflow and vocal fold tissue dynamics. Studying these fluid-structure interactions can contribute to the understanding of the mechanisms of speech production, leading to improved surgical, clinical, and pedagogical care. Aside from experiments using excised larynges (e.g., Berry et al., 2001) and a model of the superficial vocal fold layer (e.g., Chan et al., 1997), no studies appear to have been reported in which self-oscillating physical models were used that were similar to the human vocal folds in the following aspects: length scale, geometry, and dynamic and mechanical behavior. This paper describes a self-oscillating physical model designed to more closely represent the human vocal folds in terms of the above key parameters. The model was constructed using a flexible polymer casting and exhibited regular, self-sustained, large-amplitude oscillations at frequencies and operating conditions close to those found in human phonation. The model demonstrated potential for further studies involving laryngeal fluid-structure interactions.


Author(s):  
Shiro Takahashi ◽  
Kunio Hasegawa ◽  
Tomomichi Nakamura

This paper introduces nuclear power plant issues described in International Atomic Energy Agency (IAEA) technical guidelines on fluid-structure interactions (FSIs). The occurrence of FSIs has been recognized for a long time in industry. It is sometimes difficult to predict the FSI phenomena accurately, however, and FSI vibration and water hammer are concerns for structural design or trouble shooting. There have been many problems caused by FSIs in nuclear power plants. In order to avoid FSI problems for newly designed components, it is important to learn from past FSI events that have occurred at actual plants. Four major types of FSI events that have been publicly disclosed are introduced here and the importance of evaluating reactor internals with respect to flow-induced vibration is noted, if the designs of the reactor internals are for prototypes or the operating conditions are changed. The especially significant internals that are susceptible to flow-induced vibration based on past experience are introduced.


Author(s):  
Michael Paidoussis ◽  
Stuart Price ◽  
Emmanuel de Langre

2010 ◽  
Vol 5 (2) ◽  
pp. 1-8
Author(s):  
Ranis N. Ibragimov ◽  
◽  
Akshin S. Bakhtiyarov ◽  
Margaret Snell ◽  
◽  
...  

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