Practical Approach to Functional Testing and Analytical Modeling of Axial Oscillation-Supported Drillstrings

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Emmanuel Omojuwa ◽  
Ramadan Ahmed ◽  
James Acquaye
Keyword(s):  
Pressure Drop ◽  
Dynamic Response ◽  
Flow Rate ◽  
Axial Displacement ◽  
Practical Approach ◽  
Functional Testing ◽  
Functional Tests ◽  
Spring Rate ◽  
New Model ◽  
Axial Oscillation

Drillstrings that include one or more axial oscillation tools (AOTs) are referred to as axial oscillation-supported drillstrings. Downhole vibrations induced by these tools in the drillstring are the most efficient method for friction reduction and improving axial force transfer in high-angle and extended-reach wells. Functional testing of axial oscillation tools prior to downhole operations and modeling the dynamic response of axial oscillation-supported drillstring systems are required to predict the performance and functionality of AOTs. This study presents a practical approach for functional testing of axial oscillation tools and a new analytical model for predicting the dynamic response of axial oscillation-supported drillstrings operating at surface conditions. The axial oscillation-supported drillstring is modeled as an elastic continuous system subjected to viscous damping, frictional contact, and displacement (support excitation). The functional test is a unique experimental test procedure designed to measure the pressure drop, pressure fluctuations, and axial displacement of an axial oscillation tool while varying the flow rate and the spring rate of the tool. The introduction of the spring rate as a variable in the new model and functional testing is unique to this study and not considered in the existing literature. Axial displacement and acceleration predicted from the new model closely agrees with the results obtained from the functional tests. The accuracy of the model is also validated with the results of two previously published functional tests. The comparisons demonstrate an average deviation of approximately 14.5% between predictions and measurements. The axial displacement and pressure drop of AOT increased with flow rate or oscillation frequency. The amplitude of axial displacement increased with frequency because of increased pressure drop.

Study of fluid flow through a channel deformed by piezoelement

2018 ◽  
Vol 13 (3) ◽  
pp. 1-10 ◽  
Author(s):  
I.Sh. Nasibullayev ◽  
E.Sh Nasibullaeva ◽  
O.V. Darintsev
Keyword(s):  
Fluid Flow ◽  
Pressure Drop ◽  
Boundary Conditions ◽  
Flow Rate ◽  
Contact Surface ◽  
Piezoelectric Element ◽  
Neumann Boundary ◽  
Differential Pressure ◽  
Physical Parameters ◽  
Flow Through

The flow of a liquid through a tube deformed by a piezoelectric cell under a harmonic law is studied in this paper. Linear deformations are compared for the Dirichlet and Neumann boundary conditions on the contact surface of the tube and piezoelectric element. The flow of fluid through a deformed channel for two flow regimes is investigated: in a tube with one closed end due to deformation of the tube; for a tube with two open ends due to deformation of the tube and the differential pressure applied to the channel. The flow rate of the liquid is calculated as a function of the frequency of the deformations, the pressure drop and the physical parameters of the liquid.

Pressure Drop Measurements for Air Flow Through Open-Cell Aluminum Foam

2004 ◽  
Author(s):  
Nihad Dukhan ◽  
Angel Alvarez
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Flow Rate ◽  
Aluminum Foam ◽  
Flow Direction ◽  
The Other ◽  
Turbulent Regime ◽  
Thick Sample ◽  
Open Cell ◽  
Two Samples

Wind-tunnel pressure drop measurements for airflow through two samples of forty-pore-per-inch commercially available open-cell aluminum foam were undertaken. Each sample’s cross-sectional area perpendicular to the flow direction measured 10.16 cm by 24.13 cm. The thickness in the flow direction was 10.16 cm for one sample and 5.08 cm for the other. The flow rate ranged from 0.016 to 0.101 m3/s for the thick sample and from 0.025 to 0.134 m3/s for the other. The data were all in the fully turbulent regime. The pressure drop for both samples increased with increasing flow rate and followed a quadratic behavior. The permeability and the inertia coefficient showed some scatter with average values of 4.6 × 10−8 m2 and 2.9 × 10−8 m2, and 0.086 and 0.066 for the thick and the thin samples, respectively. The friction factor decayed with the Reynolds number and was weakly dependent on the Reynolds number for Reynolds number greater than 35.

Simultaneous Measuring Method for Both Volumetric Flow Rates of Air-Water Mixture Using a Turbine Flowmeter

1996 ◽  
Vol 118 (1) ◽  
pp. 29-35 ◽  
Author(s):  
K. Minemura ◽  
K. Egashira ◽  
K. Ihara ◽  
H. Furuta ◽  
K. Yamamoto
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Volumetric Flow Rate ◽  
Oil Field ◽  
Liquid Density ◽  
Water Mixture ◽  
Rotor Speed ◽  
Flow Rates ◽  
Field Development ◽  
Turbine Flowmeter

A turbine flowmeter is employed in this study in connection with offshore oil field development, in order to measure simultaneously both the volumetric flow rates of air-water two-phase mixture. Though a conventional turbine flowmeter is generally used to measure the single-phase volumetric flow rate by obtaining the rotational rotor speed, the method proposed additionally reads the pressure drop across the meter. After the pressure drop and rotor speed measured are correlated as functions of the volumetric flow ratio of the air to the whole fluid and the total volumetric flow rate, both the flow rates are iteratively evaluated with the functions on the premise that the liquid density is known. The evaluated flow rates are confirmed to have adequate accuracy, and thus the applicability of the method to oil fields.

Experimental Investigation of Effect of Tip Coolant Ejection on Internal Flow Characteristics Within a Realistic Blade Coolant Channel

2013 ◽  
Author(s):  
Jian Pu ◽  
Zhaoqing Ke ◽  
Jianhua Wang ◽  
Lei Wang ◽  
Hongde You
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Turbine Blade ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Flow Ratio ◽  
Lp Turbine ◽  
Mass Flow Ratio

This paper presents an experimental investigation on the characteristics of the fluid flow within an entire coolant channel of a low pressure (LP) turbine blade. The serpentine channel, which keeps realistic blade geometry, consists of three passes connected by a 180° sharp bend and a semi-round bend, 2 tip exits and 25 trailing edge exits. The mean velocity fields within several typical cross sections were captured using a particle image velocimetry (PIV) system. Pressure and flow rate at each exit were determined through the measurements of local static pressure and volume flow rate. To optimize the design of LP turbine blade coolant channels, the effect of tip ejection ratio (ER) from 180° sharp bend on the flow characteristics in the coolant channel were experimentally investigated at a series of inlet Reynolds numbers from 25,000 to 50,000. A complex flow pattern, which is different from the previous investigations conducted by a simplified square or rectangular two-pass U-channel, is exhibited from the PIV results. This experimental investigation indicated that: a) in the main flow direction, the regions of separation bubble and flow impingement increase in size with a decrease of the ER; b) the shape, intensity and position of the secondary vortices are changed by the ER; c) the mass flow ratio of each exit to inlet is not sensitive to the inlet Reynolds number; d) the increase of the ER reduces the mass flow ratio through each trailing edge exit to the extent of about 23–28% of the ER = 0 reference under the condition that the tip exit located at 180° bend is full open; e) the pressure drop through the entire coolant channel decreases with an increase in the ER and inlet Reynolds number, and a reduction about 35–40% of the non-dimensional pressure drop is observed at different inlet Reynolds numbers, under the condition that the tip exit located at 180° bend is full open.

Nonlinear Axial and Transverse Oscillation and Control of a PZT Laminated Distributed Structronic System

2000 ◽  
Author(s):  
H. S. Tzou ◽  
J. H. Ding ◽  
W. K. Chai
Keyword(s):  
Distributed Control ◽  
Shape Control ◽  
Geometrical Nonlinearity ◽  
Axial Displacement ◽  
Beam Model ◽  
Control Effect ◽  
Laminated Beam ◽  
Practical Applications ◽  
Axial Oscillation ◽  
And Control

Abstract Piezoelectric laminated distributed systems have broad applications in many new smart structures and structronic systems. As the shape control becomes an essential issue in practical applications, the nonlinear large deformation has to be considered, and thus, the geometrical nonlinearity has to be incorporated. Two electromechanical partial differential equations, one in the axial direction and the other in the transverse direction, are derived for the nonlinear PZT laminated beam model. The conventional approach is to neglect the axial oscillation and distributed sensing and control of the distributed laminated beam is evaluated, excluding the effect of axial oscillation. In this paper, influence of the axial displacement to the dynamics and distributed control effect is evaluated. Analysis results reveal that the axial displacement, indeed, has significant influence to the dynamic and distributed control responses of the nonlinear distributed PZT laminated beam structronics systems.

Heat Transfer and Pressure Drop in a Converging Pedestal Array With Exit Area Variation

2018 ◽  
Author(s):  
L. W. Soma ◽  
F. E. Ames ◽  
S. Acharya
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Flow Rate ◽  
Film Cooling ◽  
Reynolds Numbers ◽  
Flow Path ◽  
Internal Cooling ◽  
Channel Measurements ◽  
Trailing Edge ◽  
Cooling Air

The trailing edge of a vane is one of the most difficult areas to cool due to a narrowing flow path, high external heat transfer rates, and deteriorating external film cooling protection. Converging pedestal arrays are often used as a means to provide internal cooling in this region. The thermally induced stresses in the trailing edge region of these converging arrays have been known to cause failure in the pedestals of conventional solidity arrays. The present paper documents the heat transfer and pressure drop through two high solidity converging rounded diamond pedestal arrays. These arrays have a 45 percent pedestal solidity. One array which was tested has nine rows of pedestals with an exit area in the last row consistent with the convergence. The other array has eight rows with an expanded exit in the last row to enable a higher cooling air flow rate. The expanded exit of the eight row array allows a 30% increase in the coolant flow rate compared with the nine row array for the same pressure drop. Heat transfer levels correlate well based on local Reynolds numbers but fall slightly below non converging arrays. The pressure drop across the array naturally increases toward the trailing edge with the convergence of the flow passage. A portion of the cooling air pressure drop can be attributed to acceleration while a portion can be attributed to flow path losses. Detailed array static pressure measurements provide a means to develop a correlation for the prediction of pressure drop across the cooling channel. Measurements have been acquired over Reynolds numbers based on exit flow conditions and the characteristic pedestal length scale ranging from 5000 to over 70,000.

Research on Two-Phase Flow Instability in Evaporator of Refrigeration System

2010 ◽  
Author(s):  
Nan Liang ◽  
Changqing Tian ◽  
Shuangquan Shao
Keyword(s):  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Two Phase Flow ◽  
Density Wave ◽  
Phase Flow ◽  
Constant Mass ◽  
Refrigeration System ◽  
Two Phase

As one kind of fluid machinery related to the two-phase flow, the refrigeration system encounters more problems of instability. It is essential to ensure the stability of the refrigeration systems for the operation and efficiency. This paper presents the experimental investigation on the static and dynamic instability in an evaporator of refrigeration system. The static instability experiments showed that the oscillatory period and swing of the mixture-vapor transition point by observation with a camera through the transparent quartz glass tube at the outlet of the evaporator. The pressure drop versus mass flow rate curves of refrigerant two phase flow in the evaporator were obtained with a negative slope region in addition to two positive slope regions, thus making the flow rate a multi-valued function of the pressure drop. For dynamic instabilities in the evaporation process, three types of oscillations (density wave type, pressure drop type and thermal type) were observed at different mass flow rates and heat fluxes, which can be represented in the pressure drop versus mass flow rate curves. For the dynamic instabilities, density wave oscillations happen when the heat flux is high with the constant mass flow rate. Thermal oscillations happen when the heat flux is correspondingly low with constant mass flow rate. Though the refrigeration system do not have special tank, the accumulator and receiver provide enough compressible volume to induce the pressure drop oscillations. The representation and characteristic of each oscillation type were also analyzed in the paper.

A Numerical Analysis on the System Impedance in a Fan Cooling System

2003 ◽  
Author(s):  
Dong-Il Kim ◽  
Ki-So Bok ◽  
Han-Bae Lee
Keyword(s):  
Numerical Analysis ◽  
Pressure Drop ◽  
Flow Rate ◽  
Pressure Difference ◽  
Cooling System ◽  
Computational Time ◽  
Computational Domain ◽  
Impedance Curve ◽  
Fan Cooling ◽  
Large Investment

To seek the fan operating point on a cooling system with fans, it is very important to determine the system impedance curve and it has been usually examined with the fan tester based on ASHRAE standard and AMCA standard. This leads to a large investment in time and cost, because it could not be executed until the system is made actually. Therefore it is necessary to predict the system impedance curve through numerical analysis so that we could reduce the measurement time and effort. This paper presents how the system impedance curve (pressure drop curve) is computed by CFD in substitute for experiment. In reverse order to the experimental principle of the fan tester, pressure difference was adopted first as inlet and outlet boundary conditions of the system and then flow rate was calculated. After determining the system impedance curve, it was compared with experimental results. Also the computational domain of the system was investigated to minimize computational time.

Identification of Design Criteria for Converter Cooling System of Permanent Magnet Direct-Drive Wind Turbine Generator

2016 ◽  
Author(s):  
Gerardo L. Augusto ◽  
Alvin B. Culaba ◽  
Laurence A. Gan Lim
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Cooling System ◽  
Volume Flow Rate ◽  
Volume Flow ◽  
Design Criteria ◽  
Direct Drive ◽  
Turbine Generator ◽  
Wind Turbine Generator ◽  
System Volume

The design criteria of converter cooling system for a 2.5 MW permanent magnet direct-drive wind turbine generator were investigated. Two (2) distribution networks with pipe sizes of DN40 and DN50 were used as basis for fluid flow analysis. The theoretical system pressure drop and system volume flow rate of converter cooling system were calculated using the governing equations of mass conservation, pump performance curve and distribution network characteristics. The system of nonlinear equations was solved using multivariable Newton-Raphson method with the solution vector determined using LU decomposition method. Numerical results suggest that the DN50 pipe provides a pressure drop limit of less than 300 Pa/m in the converter cooling system better than the pressure drop obtained from a DN40 pipe. The system volume flow rate of DN50 pipe was found to be above the operating limit of heat exchanger requirement of 135.30 L/min which needs to dissipate heat with a minimum of 50 kW.

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