Multiphase Flow Performance Prediction Model for Twin-Screw Pump

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Peng Liu ◽  
Abhay Patil ◽  
Gerald Morrison
Keyword(s):  
Multiphase Flow ◽  
Operating Conditions ◽  
Model Verification ◽  
Leakage Flow ◽  
Screw Pump ◽  
New Model ◽  
Choked Flow ◽  
Screw Length ◽  
Wide Range ◽  
Twin Screw

This study is focused on the development and validation of an analytical model to predict the performance characteristics of multiphase flow twin-screw pump for wide range of operating conditions. A 200 HP, 635 gpm capacity multiphase flow twin-screw pump was tested with inlet pressure varying from 15 psig to 100 psig at gas void fraction (GVF) varying from 0% to 100% to validate the model. A new model is proposed to study the leakage flow in the twin screw pump. Adiabatic compressible flow is assumed in the circumferential clearance. The acceleration of the two-phase flow is taken into account in the new model. The change of Mach number of the leakage flow in the clearance and the possibility of choked flow at the outlet of the clearance was studied. Model provided important information about pressure distribution across the screw length, volumetric efficiency of the pump, and chocked flow condition. Model verification using experimental data concluded the paper.

3D Flow Simulation of a Twin-Screw Pump for the Analysis of Gap Flow Characteristics

2021 ◽  
Author(s):  
Ali Hassannejadmoghaddam ◽  
Boris Kutschelis ◽  
Frank Holz ◽  
Tomas Börjesson ◽  
Romuald Skoda
Keyword(s):  
Flow Rate ◽  
Volume Flow Rate ◽  
Overset Grid ◽  
3D Flow ◽  
Screw Pump ◽  
Pump Performance ◽  
Gap Flow ◽  
Wide Range ◽  
Twin Screw ◽  
Pump Head

Abstract Unsteady 3D flow simulations on a twin-screw pump are performed for an assessment of the radial, circumferential and flank gap flow effect on the pump performance. By means of the overset grid technique rigid computational grids around the counter-rotating spindles yield a high cell quality and a high spatial resolution of the gap backflow down to the viscous sublayer in terms of y^+ < 1 . An optimization of the hole-cutting process is performed on a generic gap flow and transferred to the complex moving gaps in the pump. Grid independence is ensured, and conservation properties of the overset grid interpolation technique are assessed. Simulation results are validated against measured pump characteristics. Pump performance in terms of pressure build-up along the flow path through the spindles and volume flow rate is presented for a wide range of spindle speed and pump head. Flow rate fluctuations are found to depend on head but hardly on speed. By a profound assessment of the respective radial, circumferential and flank gap contribution to the total backflow, the importance of the most complex flank gap is pointed out. Backflow rate characteristics in dependence on the pump head and the pump speed are presented.

A New Model for Predicting Flow Boiling Heat Transfer Coefficients in Horizontal Microfin Tubes

2016 ◽  
Author(s):  
Reem Merchant ◽  
Sunil Mehendale
Keyword(s):  
Heat Transfer ◽  
Flow Boiling ◽  
Operating Conditions ◽  
Transfer Coefficients ◽  
Experimental Database ◽  
New Model ◽  
Heat Transfer Coefficients ◽  
New Correlation ◽  
Wide Range ◽  
Microfin Tubes

The objective of the current work is to present a new correlation for predicting heat transfer coefficients (HTCs) for flow boiling in horizontal microfin tubes. Correlations to predict HTCs have been proposed by numerous authors such as Yu et al., Thome et al., Cavallini et al., Yun et al., Chamra and Mago, Wu et al., and other researchers. The correlations proposed are semi-empirical due to the difficulties associated with modeling the physics of flow boiling in microfin tubes. The above correlations are based on smooth tube flow boiling correlations which are modified to capture the effect of the inner grooves in the microfin tubes on the boiling process. In a previous work, it has been demonstrated that no single correlation can reasonably predict the flow boiling HTCs over a wide range of operating conditions and tube geometric parameters (Merchant and Mehendale). A new model has been proposed and validated using an experimental database of 1576 points from published literature. For the full dataset, the new correlation has X30% of 67.3%, compared to Cavallini et al. and Wu et al. with X30% of 44.2% and 40.6% respectively. The performance of the new model for tube diameters less than and greater than 5 mm has also been discussed for halogenated refrigerants and CO2.

Experimental and Analytical Investigation of a Novel Multistage Twin-Screw Pump

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
P. Liu ◽  
G. Morrison ◽  
A. Patil
Keyword(s):  
Analytical Investigation ◽  
Differential Pressure ◽  
Operating Conditions ◽  
Working Fluid ◽  
Volumetric Fraction ◽  
Screw Pump ◽  
Rotating Speed ◽  
Twin Screw ◽  
Rate Capacity ◽  
Good Agreement

Abstract The performance of a multistage electrical submersible twin-screw pump (ESTSP) was evaluated under different operating conditions. The effect of working fluid, differential pressure, gas volumetric fraction (GVF), and pump rotating speed on the behavior of the ESTSP has been studied. Mineral oil and water were selected as test liquids. The pump was tested with a maximum differential pressure of 1000 psig. The GVF varies from 0% to 85%. The flow rate capacity and the volumetric efficiency were investigated in this research. An existing model to predict leakage flow of the single stage twin-screw pump is improved by extending the application for the multistage pumps. The model shows good agreement with experimental data under various operating conditions.

Treatment of Rate-Transient Analysis During Boundary-Dominated Flow

SPE Journal ◽  
2018 ◽  
Vol 23 (04) ◽  
pp. 1145-1165 ◽  
Author(s):  
H.. Behmanesh ◽  
L.. Mattar ◽  
J. M. Thompson ◽  
D. M. Anderson ◽  
D. W. Nakaska ◽  
...  
Keyword(s):  
Multiphase Flow ◽  
Transient Analysis ◽  
Single Phase ◽  
Material Balance ◽  
Operating Conditions ◽  
New Method ◽  
Productivity Index ◽  
Production Data ◽  
Rate Transient Analysis ◽  
Wide Range

Summary Significant advances have been made in the development of analytical models for performing rate-transient analysis (RTA) for single-phase oil and gas reservoirs. The primary complication associated with the adaptation of these solutions to wells exhibiting multiphase flow is the single-phase assumption in the development of the material-balance time function. Despite some efforts in modifying existing dry-gas formulations for use with gas/condensate reservoirs, that approach is not practical for analyzing multiphase flow from oil wells with multiphase-flow characteristics. In this work, we present a simple yet semianalytical model that provides a solution for analyzing production data from wells exhibiting multiphase flow during boundary-dominated flow periods. The solution is obtained by combining the material-balance equation and the productivity index (PI) for all flowing phases. Appropriately defined total pseudopressure and total pseudotime are introduced to handle the associated multiphase nonlinearities in the governing flow equations of oil, gas, and water phases simultaneously. A generalized flowing-material-balance (FMB) equation is derived from the total pseudovariables to estimate original fluid in place and drainage area (given volumetric input). The presented model provides a theoretical framework for analyzing production data considering a wide variety of reservoir-fluid systems. The new method is validated against numerical simulation, covering a wide range of fluid properties and operating conditions. In all simulated cases, the new method matches simulation input acceptably. Two field examples are also analyzed to demonstrate the practical applicability of this approach. This work serves as a practical and simple engineering tool for production-data analysis on wells exhibiting single and multiphase flow during boundary-dominated flow.

Forces on Bends and T-Joints due to Multiphase Flow

2010 ◽  
Author(s):  
S. P. C. Belfroid ◽  
M. F. Cargnelutti ◽  
W. Schiferli ◽  
Marlies van Osch
Keyword(s):  
Multiphase Flow ◽  
Flow Regime ◽  
Slug Flow ◽  
Annular Flow ◽  
Gas Flow ◽  
Stratified Flow ◽  
Operating Conditions ◽  
Large Radius ◽  
Flow Conditions ◽  
Wide Range

To be able to assess the mechanical integrity of piping structures for loading to multiphase flow conditions, air-water experiments were carried out in a horizontal 1″ pipe system. Forces and accelerations were measured on a number of bends and T-joint configurations for a wide range of operating conditions. Five different configurations were measured: a baseline case consisting of a straight pipe only, a sharp edged bend, a large radius bend, a symmetric T-joint and a T-joint with one of the arms closed off. The gas flow was varied from a superficial velocity of 0.1 to 30 m/s and the liquid flow was varied from 0.05 to 2 m/s. This operating range ensures that the experiment encompasses all possible flow regimes. The magnitude of the measured forces was found to vary over a wide range depending on the flow regime. For slug flow conditions very high force levels were measured, up to 4 orders of magnitude higher than in single phase flow for comparable velocities. The annular flow regime resulted in the (relative) lowest forces, although the absolute amplitude is of the same order as in the case of slug flow. In case of slug flow, the measured results can be described assuming a simple slug unit model. For both the frequency and amplitude the available models can be used in assessments. In annular and stratified flow a different model is required, since no slug unit is present. Instead, the amplitude of the excitation force can be estimated using mixture properties. To predict the main frequency for the annular flow and stratified flow additional experiments are required.

Comparison of Deterministic and Linear Cosine Spatial Filtering of Transmission Electron Micrographs

1972 ◽  
Vol 30 ◽  
pp. 596-597
Author(s):  
David A. Ansley
Keyword(s):  
Spherical Aberration ◽  
Focal Length ◽  
Chromatic Aberration ◽  
Spatial Filter ◽  
Operating Conditions ◽  
Objective Lens ◽  
List Type ◽  
Spatial Filters ◽  
Transmission Electron ◽  
Wide Range

The coherence of the electron flux of a transmission electron microscope (TEM) limits the direct application of deconvolution techniques which have been used successfully on unmanned spacecraft programs. The theory assumes noncoherent illumination. Deconvolution of a TEM micrograph will, therefore, in general produce spurious detail rather than improved resolution.A primary goal of our research is to study the performance of several types of linear spatial filters as a function of specimen contrast, phase, and coherence. We have, therefore, developed a one-dimensional analysis and plotting program to simulate a wide 'range of operating conditions of the TEM, including adjustment of the:(1) Specimen amplitude, phase, and separation(2) Illumination wavelength, half-angle, and tilt(3) Objective lens focal length and aperture width(4) Spherical aberration, defocus, and chromatic aberration focus shift(5) Detector gamma, additive, and multiplicative noise constants(6) Type of spatial filter: linear cosine, linear sine, or deterministic

Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Grain Boundary ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Operating Conditions ◽  
Structure And Properties ◽  
Steam Turbines ◽  
Friction Forces ◽  
Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

Nitrogen Removal from Anaerobically-Treated Leachate

1984 ◽  
Vol 19 (1) ◽  
pp. 87-100
Author(s):  
D. Prasad ◽  
J.G. Henry ◽  
P. Elefsiniotis
Keyword(s):  
Nitrogen Removal ◽  
Air Flow ◽  
Operating Conditions ◽  
Air Flow Rate ◽  
Flow Rates ◽  
Anaerobic Filter ◽  
Ph Values ◽  
Wide Range ◽  
Ammonia Desorption ◽  
Effects Of Ph

Abstract Laboratory studies were conducted to demonstrate the effectiveness of diffused aeration for the removal of ammonia from the effluent of an anaerobic filter treating leachate. The effects of pH, temperature and air flow on the process were studied. The coefficient of desorption of ammonia, KD for the anaerobic filter effluent (TKN 75 mg/L with NH3-N 88%) was determined at pH values of 9, 10 and 11, temperatures of 10, 15, 20, 30 and 35°C, and air flow rates of 50, 120, and 190 cm3/sec/L. Results indicated that nitrogen removal from the effluent of anaerobic filters by ammonia desorption was feasible. Removals exceeding 90% were obtained with 8 hours aeration at pH of 10, a temperature of 20°C, and an air flow rate of 190 cm3/sec/L. Ammonia desorption coefficients, KD, determined at other temperatures and air flow rates can be used to predict ammonia removals under a wide range of operating conditions.

scholarly journals Applications of Biocatalysts for Sustainable Oxidation of Phenolic Pollutants: A Review

2021 ◽  
Vol 13 (15) ◽  
pp. 8620
Author(s):  
Sanaz Salehi ◽  
Kourosh Abdollahi ◽  
Reza Panahi ◽  
Nejat Rahmanian ◽  
Mozaffar Shakeri ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Operating Conditions ◽  
Phenolic Pollutants ◽  
Petroleum Refinery Wastewater ◽  
Start Up ◽  
Low Concentrations ◽  
Effective Removal ◽  
Wide Range ◽  
Loading Effects ◽  
Spent Caustic

Phenol and its derivatives are hazardous, teratogenic and mutagenic, and have gained significant attention in recent years due to their high toxicity even at low concentrations. Phenolic compounds appear in petroleum refinery wastewater from several sources, such as the neutralized spent caustic waste streams, the tank water drain, the desalter effluent and the production unit. Therefore, effective treatments of such wastewaters are crucial. Conventional techniques used to treat these wastewaters pose several drawbacks, such as incomplete or low efficient removal of phenols. Recently, biocatalysts have attracted much attention for the sustainable and effective removal of toxic chemicals like phenols from wastewaters. The advantages of biocatalytic processes over the conventional treatment methods are their ability to operate over a wide range of operating conditions, low consumption of oxidants, simpler process control, and no delays or shock loading effects associated with the start-up/shutdown of the plant. Among different biocatalysts, oxidoreductases (i.e., tyrosinase, laccase and horseradish peroxidase) are known as green catalysts with massive potentialities to sustainably tackle phenolic contaminants of high concerns. Such enzymes mainly catalyze the o-hydroxylation of a broad spectrum of environmentally related contaminants into their corresponding o-diphenols. This review covers the latest advancement regarding the exploitation of these enzymes for sustainable oxidation of phenolic compounds in wastewater, and suggests a way forward.

scholarly journals Wide range continuously tunable and fast thermal switching based on compressible graphene composite foams

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tingting Du ◽  
Zixin Xiong ◽  
Luis Delgado ◽  
Weizhi Liao ◽  
Joseph Peoples ◽  
...  
Keyword(s):  
Thermal Management ◽  
Dynamic Control ◽  
Operating Conditions ◽  
Dynamic Thermal Management ◽  
Graphene Composite ◽  
Continuous Tuning ◽  
Composite Foams ◽  
Wide Range ◽  
Thermal Switches ◽  
Thermal Switching

AbstractThermal switches have gained intense interest recently for enabling dynamic thermal management of electronic devices and batteries that need to function at dramatically varied ambient or operating conditions. However, current approaches have limitations such as the lack of continuous tunability, low switching ratio, low speed, and not being scalable. Here, a continuously tunable, wide-range, and fast thermal switching approach is proposed and demonstrated using compressible graphene composite foams. Large (~8x) continuous tuning of the thermal resistance is achieved from the uncompressed to the fully compressed state. Environmental chamber experiments show that our variable thermal resistor can precisely stabilize the operating temperature of a heat generating device while the ambient temperature varies continuously by ~10 °C or the heat generation rate varies by a factor of 2.7. This thermal device is promising for dynamic control of operating temperatures in battery thermal management, space conditioning, vehicle thermal comfort, and thermal energy storage.

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