Including Housing–Casing Fluid in a Lateral Rotordynamics Analysis on Electric Submersible Pumps

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Clay S. Norrbin ◽  
Dara W. Childs ◽  
Stephen Phillips
Keyword(s):  
Natural Frequency ◽  
High Viscosity ◽  
Running Speed ◽  
Pump Speed ◽  
Pump Rotor ◽  
New Findings ◽  
Pump Housing ◽  
Reaction Forces ◽  
Stiff Spring ◽  
The Impact

Stability and synchronous-response predictions, which were presented by Childs et al. (2014, “A Lateral Rotordynamics Primer on Electric Submersible Pumps (ESPs) for Deep Subsea Applications,” 43th International Pump Users Symposium, Texas A&M University, College Station, TX, pp. 1–18), are re-evaluated to include the effect of the fluid between the pump housing and well casing. Conclusions are made based on these new findings. The same two-line rotor–housing model is used to model the pump's rotor and its housing. The model dimensions are based on direct measurements of an ESP. The pump rotor and pump housing are only connected together at each stage by reaction forces and moments from seals and bushings. The rotor model is pinned to the housing at the rotor's ends. The housing model is pinned to ground at its ends. Synchronous response predictions are presented for: (1) relative rotor–housing motion and (2) housing velocity-response amplitudes. When handling viscosity of water, the rotor–housing model is predicted to be stable at new (centered) 1× clearances but rapidly becomes unstable with enlarged clearances (2× and 3×), primarily due to rapidly dropping rotor–housing natural frequencies. The impact of introducing effective swirl brakes for the stages' wear ring seals was investigated for a pump running at 3600 rpm. Their predicted impact on stability and synchronous response was: (1) Onset speeds of instabilities (OSIs) were elevated well above running speed and (2) synchronous response amplitudes were reduced modestly. Housing-response amplitudes varied considerably with the choice of housing-termination locations. For a pump rotor length of Lr, varying the lengths of a centered housing over 1.5 Lr, 2 Lr, and 3 Lr changes the housing's natural frequency. This natural frequency can coincide with the running speed with proper termination conditions. If the running speed and natural frequency coincide, large housing vibration amplitudes associated with resonance would exceed most vibration regulations; however, relative rotor–stator response amplitudes were a small fraction of clearances for all the cases. When handling emulsions at markedly higher viscosities, with a pump speed of 3600 rpm and new centered clearances, the predicted OSI was below 300 rpm. The OSI rapidly increased as the seals were displaced eccentrically, quickly elevating the first rotor–stator natural frequency above 1800 rpm and the OSI above 3600 rpm. With the model stabilized at 0.2 eccentricity, the synchronous relative rotor–housing amplitudes were a small fraction of seal clearances. Swirl brakes were not predicted to be effective in elevating pump OSIs for high viscosity fluids with new clearances; however, they became effective as clearances were increased. An ESP housing can contact the well casing in many possible scenarios (axial locations, contact-area length or girth, etc.). A midspan, point radial contact was examined and modeled as a stiff-spring connection from the housing to ground. For both water and oil–water emulsions, a stiff housing-to-casing contact produced major elliptical housing motion (versus circular motion without contact). However, it had a comparably minor impact on relative rotor–housing response amplitudes or rotordynamic stability.

Including Housing-Casing Fluid in a Lateral Rotordynamics Analysis on Electric Submersible Pumps

2016 ◽  
Author(s):  
Clay S. Norrbin ◽  
Dara W. Childs ◽  
Stephen Phillips
Keyword(s):  
Natural Frequency ◽  
High Viscosity ◽  
Running Speed ◽  
Pump Speed ◽  
Pump Rotor ◽  
New Findings ◽  
Pump Housing ◽  
Reaction Forces ◽  
Stiff Spring ◽  
The Impact

Stability and synchronous-response predictions, which were presented in the paper “A Lateral Rotordynamics Primer on Electric Submersible Pumps (ESPs) for Deep Subsea Applications” [1], are reevaluated to include the effect of the fluid between the pump housing and well casing. Conclusions are made based on these new findings. The same two-line rotor-housing model is used to model the pump’s rotor and its housing. The model dimensions are based on direct measurements of an ESP. The pump rotor and pump housing are only connected together at each stage by reaction forces and moments from seals and bushings. The rotor model is pinned to the housing at the rotor’s ends. The housing model is pinned to ground at its ends. Synchronous response predictions are presented for: (1) relative rotor-housing motion, and (2) housing velocity-response amplitudes. When handling viscosity of water, the rotor-housing model is predicted to be stable at new (centered) 1X clearances but rapidly becomes unstable with enlarged clearances (2X, 3X), primarily due to rapidly dropping rotor-housing natural frequencies. The impact of introducing effective swirl brakes for the stages’ wear ring seals was investigated for a pump running at 3600 rpm. Their predicted impact on stability and synchronous response were: (1) Onset speeds of instabilities (OSIs) were elevated well above running speed, and (2) Synchronous response amplitudes were reduced modestly. Housing-response amplitudes varied considerably with the choice of housing-termination locations. For a pump rotor length of Lr, varying the lengths of a centered housing over 1.5Lr, 2Lr, and 3Lr changes the housing’s natural frequency. This natural frequency can coincide with the running speed with proper termination conditions. If the running speed coincided large housing vibration amplitudes associated with resonance would exceed most vibration regulations; however, relative rotor-stator-response amplitudes were a small fraction of clearances for all cases. When handling emulsions at markedly higher viscosities, with a pump speed of 3600 rpm and new centered clearances, the predicted OSI was below 300 rpm. The OSI rapidly increased as the seals were displaced eccentrically, quickly elevating the 1st rotor-stator natural frequency above 1800 rpm and the OSI above 3600 rpm. With the model stabilized at 0.2 eccentricity, the synchronous relative rotor-housing amplitudes were a small fraction of seal clearances. Swirl brakes were not predicted to be effective in elevating pump OSIs for high viscosity fluids with new clearances; however, they became effective as clearances were increased. An ESP housing can contact the well casing in many possible scenarios (axial locations, contact-area length or girth, etc.). A mid-span, point radial contact was examined and modeled as a stiff-spring connection from the housing to ground. For both water and oil-water emulsions, a stiff housing-to-casing contact produced major elliptical housing motion (versus circular motion without contact). However, it had a comparably minor impact on relative rotor-housing response amplitudes or rotordynamic stability.

Housingless ESPs for Slim Completion Wells

2021 ◽  
Author(s):  
Jinjiang Xiao ◽  
Chidirim Ejim
Keyword(s):  
High Speed ◽  
Current Approach ◽  
Outer Diameter ◽  
Pump Design ◽  
Pump Speed ◽  
Dynamic Head ◽  
Pump Housing ◽  
The Impact ◽  
Well Completions ◽  
Outside Diameter

Abstract This paper describes a new electrical submersible pump (ESP) design concept to overcome the challenges of applications in slim well completions or thru-tubing deployment. The housing of the conventional pump is removed, allowing the pump impellers to have a larger diameter. The impact of this design change on pump hydraulic performance is assessed in this paper. Downhole ESPs operate in environments where space is limited radially. This is especially the case for slim completions or for thru-tubing rigless deployment. To provide the required rate and total dynamic head, the current approach is to use permanent magnetic motors and operate the slim systems at rotational speed over the conventional speed of 3500-4000 RPM. High-speed operations require new pump stage designs to minimize erosion and vibration. This paper provides an alternative pump design, which removes the pump housing with the benefit of increasing the impeller tip diameter, and hence potentially reducing pump length and operational speed. To ensure the pump retains the well fluids, the diffusers are designed to be externally threaded with an O-ring feature. The centrifugal pump affinity laws are applied to evaluate the impact of removing the pump housing and increasing the impeller outside diameter. A typical ESP housing wall thickness is about 0.18-0.25 inch. With the housing removed, the incremental space available for the impeller tip to occupy is increased by 0.36-0.5 inch. Analysis shows that, for the same pump speed as a conventional pump with a housing, a housingless pump will increase the head generated by 23-32%, and the rate capacity about 36-51%, depending on the pump series. In general, the smaller the pump outer diameter, the greater the flow and head capacity increase. This is because the available space due to removing the housing becomes a considerable size of the impeller tip diameter for the smaller series pumps. The elimination of pump housing enables impellers with a larger diameter to be used to generate more head per stage. In comparison to a conventional pump of the same outside diameter, and providing the same amount of total dynamic head, the housingless pump can have fewer stages and a shorter length or operate at a reduced speed. The reduced length can help mitigating pump-bending stress for installation in deviated or horizontal wells. The reduction in required operating speeds will reduce pump wears, heat generation and vibration. The housingless ESPs have applications for slim well completions or thru-tubing deployments.

Influence of the distribution of the shear walls on the seismic response of the buildings

2020 ◽  
Vol 15 (1) ◽  
pp. 37-44
Author(s):  
El Mehdi Echebba ◽  
Hasnae Boubel ◽  
Oumnia Elmrabet ◽  
Mohamed Rougui
Keyword(s):  
Structural Analysis ◽  
Seismic Response ◽  
Natural Frequency ◽  
Structural Design ◽  
Structural Response ◽  
Shear Walls ◽  
Structural Elements ◽  
Analysis Software ◽  
Ansys Apdl ◽  
The Impact

Abstract In this paper, an evaluation was tried for the impact of structural design on structural response. Several situations are foreseen as the possibilities of changing the distribution of the structural elements (sails, columns, etc.), the width of the structure and the number of floors indicates the adapted type of bracing for a given structure by referring only to its Geometric dimensions. This was done by studying the effect of the technical design of the building on the natural frequency of the structure with the study of the influence of the distribution of the structural elements on the seismic response of the building, taking into account of the requirements of the Moroccan earthquake regulations 2000/2011 and using the ANSYS APDL and Robot Structural Analysis software.

scholarly journals New findings on iron absorption conditioning factors

2004 ◽  
Vol 4 (3) ◽  
pp. 241-248 ◽  
Author(s):  
Rute Cândida Pereira ◽  
Alcides da Silva Diniz ◽  
Luiz Oscar Cardoso Ferreira
Keyword(s):  
Iron Absorption ◽  
The Body ◽  
Vulnerable Groups ◽  
Deficiency Anemia ◽  
Public Health Issue ◽  
Conditioning Factors ◽  
Risk Increase ◽  
New Findings ◽  
Intake Regulation ◽  
The Impact

The authors focus iron intake regulation in the body and the probable mechanisms related to iron absorption. They analyze the impact of iron absorption deficiency resulting in iron deficiency anemia, a public health issue of great impact in the world influencing child and maternal health risk increase. This paper aims at highlighting the problems affecting the uptake or inhibiting processes of iron absorption in an attempt to correlate information on conditioning factors and current findings. This study is a document based descriptive study comprising literature review. In food, iron has different forms, such as the heme and non-heme forms following different absorption pathways with different efficiency rates, depending on conditioning factors, such as diet profile, physiological aspects, iron chemical state, absorption regulation, transportation, storing, excretion and the presence of disease, They also discuss the current difficulties in dealing with iron nutritional deficiency in vulnerable groups, children and pregnant women, and focus data on iron consumption, adhesion to breast feeding and the frequency of prenatal care visits.

scholarly journals Financial Inclusion and Firms Growth in Manufacturing Sector: A Threshold Regression Analysis in Selected Asean Countries

Economies ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 80
Author(s):  
Rosmah Nizam ◽  
Zulkefly Abdul Karim ◽  
Tamat Sarmidi ◽  
Aisyah Abdul Rahman
Keyword(s):  
Financial Services ◽  
Firm Growth ◽  
Manufacturing Sector ◽  
Threshold Level ◽  
Financial Inclusion ◽  
Manufacturing Firm ◽  
New Findings ◽  
Asean Countries ◽  
The Impact ◽  
Threshold Point

This paper examines the effect of financial inclusion on the firm growth of the manufacturing sector (513 firms) in selected ASEAN countries (Malaysia, Philippines, and Vietnam) using a cross-section threshold estimation technique. The levels of financial inclusion across firms were measured based on the distribution of financial services (access to credit). The main findings revealed that there is a non-monotonic effect of financial inclusion on the firm’s growth. These findings show that the impact of financial inclusion on firm growth in the manufacturing sector is significantly positive below a threshold point, and turns to significantly negative after a certain threshold point has been reached. These new findings suggest that manufacturing firm owners and banking institutions should deepen their financial inclusion efforts, and limit the distribution of credit access within the optimum value or threshold level in promoting the growth of the firm.

New Findings on Older People’s Life Expectancies Confirm Gompertz Law: The Impact on the Value of Securitized Life Settlements

2014 ◽  
Vol 20 (2) ◽  
pp. 66-73 ◽  
Author(s):  
Leonid A. Gavrilov ◽  
Natalia S. Gavrilova ◽  
Charles Austin Stone ◽  
Anne Zissu
Keyword(s):  
New Findings ◽  
Life Settlements ◽  
Gompertz Law ◽  
The Impact

Study on a Novel MEMS High G Acceleration Sensor

2012 ◽  
Vol 490-495 ◽  
pp. 499-503
Author(s):  
Ping Li ◽  
Yun Bo Shi ◽  
Jun Liu ◽  
Shi Qiao Gao
Keyword(s):  
Resonant Frequency ◽  
Natural Frequency ◽  
Impact Load ◽  
Hopkinson Bar ◽  
Experimental Results ◽  
Structure Parameters ◽  
Acceleration Sensor ◽  
Piezoresistive Effect ◽  
Sensor Structure ◽  
The Impact

This paper presents a novel MEMS high g acceleration sensor based on piezoresistive effect. For the designed sensor structure, the formula of stress, natural frequency and damping was derived in theory, and the resonant frequency can up to 500kHz. After the structure parameters were designed, the sensor was fabricated by the standard processing technology, and the sensitivity was tested by Hopkinson bar. According to the experimental results, the sensitivity of the high g acceleration sensor is 0.125μV/g at the impact load of 164,002g.

Free vibration analysis and post-critical free vibrations of nanocomposite rotating beams reinforced with graphene platelet

2021 ◽  
pp. 107754632110511
Author(s):  
Arameh Eyvazian ◽  
Chunwei Zhang ◽  
Farayi Musharavati ◽  
Afrasyab Khan ◽  
Mohammad Alkhedher
Keyword(s):  
Natural Frequency ◽  
Thermal Environment ◽  
Rotational Velocity ◽  
Equations Of Motion ◽  
Free Vibration Analysis ◽  
Beam Theory ◽  
Weight Fraction ◽  
Free Vibrations ◽  
Graphene Platelet ◽  
The Impact

Treatment of the first natural frequency of a rotating nanocomposite beam reinforced with graphene platelet is discussed here. In regard of the Timoshenko beam theory hypothesis, the motion equations are acquired. The effective elasticity modulus of the rotating nanocomposite beam is specified resorting to the Halpin–Tsai micro mechanical model. The Ritz technique is utilized for the sake of discretization of the nonlinear equations of motion. The first natural frequency of the rotating nanocomposite beam prior to the buckling instability and the associated post-critical natural frequency is computed by means of a powerful iteration scheme in reliance on the Newton–Raphson method alongside the iteration strategy. The impact of adding the graphene platelet to a rotating isotropic beam in thermal ambient is discussed in detail. The impression of support conditions, and the weight fraction and the dispersion type of the graphene platelet on the acquired outcomes are studied. It is elucidated that when a beam has not undergone a temperature increment, by reinforcing the beam with graphene platelet, the natural frequency is enhanced. However, when the beam is in a thermal environment, at low-to-medium range of rotational velocity, adding the graphene platelet diminishes the first natural frequency of a rotating O-GPL nanocomposite beam. Depending on the temperature, the post-critical natural frequency of a rotating X-GPL nanocomposite beam may be enhanced or reduced by the growth of the graphene platelet weight fraction.

Footwear and Elevated Heel Influence On Barbell Back Squat: a Review

2021 ◽  
Author(s):  
Aaron Michael Pangan ◽  
Matthew J Leineweber
Keyword(s):  
Ground Reaction Forces ◽  
Specific Effects ◽  
Back Squat ◽  
Running Shoes ◽  
Different Types ◽  
Reaction Forces ◽  
Joint Loads ◽  
The Impact ◽  
Kinematics And Kinetics ◽  
Full Body

Abstract The back squat is one of the most effective exercises in strengthening the muscles of the lower extremity. Understanding the impact of footwear has on the biomechanics is imperative for maximizing the exercise training potential, preventing injury, and rehabilitating from injury. This review focuses on how different types of footwear affect the full-body kinematics, joint loads, muscle activity, and ground reaction forces in athletes of varying experience performing the weighted back squat. The literature search was conducted using three databases, and fourteen full-text articles were ultimately included in the review. The majority of these studies demonstrated that the choice of footwear directly impacts kinematics and kinetics. Weightlifting shoes were shown to decrease trunk lean and generate more plantarflexion relative to running shoes and barefoot lifting. Elevating the heel through the use of external squat wedges is popular clinical exercise during rehabilitation and was shown to provide similar effects to WLS. Additional research with a broader array of populations, particularly novice and female weightlifters, should be conducted to generalize the research results to non-athlete populations. Further work is also needed to characterize the specific effects of sole stiffness and heel elevation height on squatting mechanics.

scholarly journals Identification of Corrosion on a Hollow Tube Using Vibration

2014 ◽  
Vol 564 ◽  
pp. 176-181
Author(s):  
S.T. Cheng ◽  
Nawal Aswan Abdul Jalil ◽  
Zamir A. Zulkefli
Keyword(s):  
Free Boundary ◽  
Boundary Conditions ◽  
Natural Frequency ◽  
Impact Loading ◽  
Structural Damage ◽  
Natural Frequencies ◽  
Localized Corrosion ◽  
Free Boundary Conditions ◽  
The Impact ◽  
Impact Vibration

Vibration based technique have so far been focused on the identification of structural damage. However, not many studies have been conducted on the corrosion identification on pipes. The objective of this paper is to identify corrosion on pipes from vibration measurements. A hollow pipe, 500 mm in length with 63.5 mm in diameter was subjected to impact loading using an impact hammer to identify the natural frequency of the tube in two conditions i) without any corrosion and ii) with an induced localized 40 mm by 40 mm corrosion at the middle of the pipe. The shift of natural frequencies of the structures under free boundary conditions was examined for each node of excitation. The results showed that there is a shift in natural frequency of the pipe, between 3 and 4 Hz near to the corrosion area. It can suggested that that the impact vibration is capable of identifying of localized corrosion on a hollow tube.

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