scholarly journals Heat dissipation of the Electrical Submersible Pump (ESP) installed in a subsea skid

2020 ◽  
Vol 75 ◽  
pp. 13
Author(s):  
Jonathan Ribeiro Martins ◽  
Daniel da Cunha Ribeiro ◽  
Fabio de Assis Ressel Pereira ◽  
Marcos Pellegrini Ribeiro ◽  
Oldrich Joel Romero
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Electric Motor ◽  
Single Phase ◽  
Heat Dissipation ◽  
Convection Heat Transfer ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Submersible Pump ◽  
Electrical Submersible Pump

The recent development of Electrical Submersible Pump (ESP) in the skid, installed in the seabed downstream of the wellhead in an offshore oil production system, is an alternative to the conventional system with the set installed at the bottom of the producing well, facilitating interventions in case of failure. The pump is driven by an electric motor whose cooling must be efficient to ensure the continuity of its operation. The heat withdrawal is performed by the fluid produced. The purpose of this article is to understand the process of electric motor cooling to the single-phase and turbulent flow with convection heat transfer in an annular geometry, which represents the space formed between a capsule and the ESP in the Skid system motor. With this objective it is employed a Computational Fluid Dynamics (CFD) code to solve the governing equations of the turbulent heat transfer single-phase flow. The standard κ-ε model with improved wall function (Enhanced Wall Treatment) is used to closure turbulence problem. This study considered flow rates range of 2200–4200 m3/d (representing Reynolds numbers range of 27 000–133 000 approximately), Prandtl numbers 7–37, three configurations of different annular geometries, one concentric and two eccentric, together with the condition of the constant temperature on the motor surface (130 °C) and capsule (4 °C). The simulations are validated by comparing the Nusselt number in the developed region with the Gnielinski correlation. It is observed that if the constant heat flux condition were used, the motor temperature would have lower values at the beginning and larger at the end of the geometry. Therefore, the higher the Nusselt number, the greater the heat transfer, thus intensifying the cooling of the electric motor. In the eccentric geometry a momentum transfer from the lower to the upper annular region is observed, causing the Nusselt number present an angular variation. In eccentric geometries the flow develops in greater lengths, observing that the greater the eccentricity, the greater this length. Finally, for the ESP in the Skid system the use of an eccentric geometry is not adequate.

scholarly journals 3D Numerical simulation of turbulent heat transfer and Fe3O4/nanofluid annular flow in sudden enlargement

2021 ◽  
Vol 321 ◽  
pp. 04014
Author(s):  
Hussein Togun
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Heat Transport ◽  
Annular Flow ◽  
Volume Concentration ◽  
Convection Heat Transfer ◽  
Turbulent Heat Transfer ◽  
Recirculation Region ◽  
Convection Heat

In this paper, 3D Simulation of turbulent Fe3O4/Nanofluid annular flow and heat transfer in sudden expansion are presented. k-ε turbulence standard model and FVM are applied with Reynolds number different from 20000 to 50000, enlargement ratio (ER) varied 1.25, 1.67, and 2, , and volume concentration of Fe3O4/Nanofluid ranging from 0 to 2% at constant heat flux of 4000 W/m2. The main significant effect on surface Nusselt number found by increases in volume concentration of Fe3O4/Nanofluid for all cases because of nanoparticles heat transport in normal fluid as produced increases in convection heat transfer. Also the results showed that suddenly increment in Nusselt number happened after the abrupt enlargement and reach to maximum value then reduction to the exit passage flow due to recirculation flow as created. Moreover the size of recirculation region enlarged with the rise in enlargement ratio and Reynolds number. Increase of volume Fe3O4/nanofluid enhances the Nusselt number due to nanoparticles heat transport in base fluid which raises the convection heat transfer. Increase of Reynolds number was observed with increased Nusselt number and maximum thermal performance was found with enlargement ratio of (ER=2) and 2% of volume concentration of Fe3O4/nanofluid. Further increases in Reynolds number and enlargement ratio found lead to reductions in static pressure.

scholarly journals A study of turbulent heat transfer in convergent-divergent shaped microchannel with ribs and cavities using CFD

2020 ◽  
Vol 14 (1) ◽  
pp. 6344-6361
Author(s):  
Pankaj Srivastava ◽  
Anupam Dewan
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Thermal Resistance ◽  
Average Nusselt Number ◽  
Three Dimensional ◽  
Fluid Mixing ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Rectangular Microchannel ◽  
Better Than

This paper presents the effects of microchannel shape with ribs and cavities on turbulent heat transfer. Three-dimensional conjugate heat transfer using the SST k-ω turbulence model has been investigated for four different microchannels, namely, rectangular, rectangular with ribs and cavities, convergent-divergent (CD) and convergent-divergent with Ribs and Cavities (CD-RC). The flow field, pressure and temperature distributions and friction factor are analyzed, and thermal resistance and average Nusselt number are compared. The thermal performance of the CD-RC microchannel is found to be better than that of other microchannels considered in terms of an average Nusselt number increased from 16% to 40%. Heat transfer increases due to a strong fluid mixing and periodic interruption of boundary-layer. It is observed that with an increase in Reynolds number (Re), the thermal resitance drops rapidly. The thermal resistance of the CD-RC microchannel is decreased by 30% than that of the rectangular microchannel for Re ranging from 2500 to 7000. However, such design of microchannel loses its heat transfer effectiveness due to a high pumping power at high values of Re.

Turbulent Heat Transfer Over a Free Rotating Disk: Analytical and Numerical Predictions Using Solutions of Direct and Inverse Problems

2001 ◽  
Author(s):  
I. V. Shevchuk
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Wall Temperature ◽  
Direct Problem ◽  
Rotating Disk ◽  
Analytical Form ◽  
Turbulent Heat Transfer ◽  
Radial Coordinate ◽  
Turbulent Heat ◽  
Numerical Predictions

Abstract All known analytical solutions of the integral equation of the turbulent thermal boundary layer for a rotating disk have been obtained for the case of direct problem. This means finding the Nusselt number at a given distribution of the wall temperature. This distribution is described by power law and is monotone (derivative of wall temperature with respect to the radial coordinate does not change its sign). Outlined in this paper is an analytical form of non-monotone distribution of the wall temperature, which provided a new analytical solution for the turbulent Nusselt number including earlier known equations as a specific particular case. The solution is based on the integral method, which proved to be more precise than known Dorfman’s approach. Chosen for validation of the proposed method were turbulent heat transfer experiments of Northrop and Owen (1988). Predictions presented include analytical studies using inverse and direct problem solutions as well as numerical simulations using polynomial approximations of the experimental wall temperature distributions.

Two-Phase Heat Transfer in a Wall-Driven Cubical Heat Sink

2016 ◽  
Author(s):  
Majid Molki
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Heat Sink ◽  
Volume Fraction ◽  
Turbulent Heat Transfer ◽  
Liquid Volume ◽  
Turbulent Heat ◽  
Fluid Temperature ◽  
Complex Flow ◽  
Liquid Volume Fraction

Turbulent heat transfer for flow of water-air mixture driven by moving walls in a cubical heat sink is investigated. One wall is maintained at an elevated temperature, while the vertical walls are at a low temperature. The cubical enclosure functions as a heat sink using water-air mixture with no phase change. Different arrangements for wall motion are considered, which include 1 to 4 moving walls. As the number of moving walls increases, the flow and heat transfer become more complex. In general, the flow reveals complex and multi-scale structures with an unsteady and evolving nature. The larger structure of the flow is resolved using Large Eddy Simulation, while the sub-grid scales are captured by the dynamic k-equation eddy-viscosity model. The focus of this work is on thermal field and heat transfer as affected by the complex flow field generated by multiple moving walls. The results indicate that the Nusselt number for the heat sink varies from 5202.8 to 7356.1, depending on the number of moving walls. Contours of fluid temperature, liquid volume fraction, local and average values of Nusselt number are among the results presented in this paper.

Splattering and Heat Transfer During Impingement of a Turbulent Liquid Jet

1992 ◽  
Vol 114 (2) ◽  
pp. 362-372 ◽  
Author(s):  
J. H. Lienhard ◽  
X. Liu ◽  
L. A. Gabour
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Heated Surface ◽  
Film Surface ◽  
Turbulent Heat Transfer ◽  
Liquid Jet ◽  
Turbulent Heat ◽  
Disturbance Analysis ◽  
Momentum Integral ◽  
Surface Disturbances

Splattering and heat transfer due to impingement of an unsubmerged, fully turbulent liquid jet is investigated experimentally and analytically. Heat transfer measurements were made along a uniformly heated surface onto which a jet impacted, and a Phase Doppler Particle Analyzer was used to measure the size, velocity, and concentration of the droplets splattered after impingement. Splattering is found to occur in proportion to the magnitude of surface disturbances to the incoming jet, and it is observed to occur only within a certain radial range, rather than along the entire film surface. A nondimensional group developed from inviscid capillary disturbance analysis of the circular jet successfully scales the splattering data, yielding predictive results for the onset of splattering and for the mass splattered. A momentum integral analysis incorporating the splattering results is used to formulate a prediction of local Nusselt number. Both the prediction and the experimental data reveal that the Nusselt number is enhanced for radial locations immediately following splattering, but falls below the nonsplattering Nusselt number at larger radii. The turbulent heat transfer enhancement upstream of splattering is also characterized.

Numerical Simulation of Turbulent Heat Transfer on a Rotating Disk With an Impinging Jet

2010 ◽  
Author(s):  
M. H. Saidi ◽  
H. Karrabi ◽  
H. B. Avval ◽  
A. Asgarshamsi
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Rotating Disk ◽  
Turbulent Heat Transfer ◽  
Maximum Temperature ◽  
Turbulent Heat ◽  
Cooling Process ◽  
Maximum Temperature Difference

A numerical study has been earned out to investigate the fluid flow structure and convective heat transfer due to a circular jet impinging on a rotating disk. The temperature distribution and convection heat transfer coefficient on the disk are calculated. Flow is considered to be steady, incompressible and turbulent. k-ε RNG model is used to model the turbulent flow. Two new criteria are introduced and used to evaluate the performance of cooling process which are maximum temperature difference on the disk and the average temperature of the disk. The first parameter shows the uniformity of temperature distribution in the disk and the second shows the effect of both thermo physical properties of the disk material and cooling process. In order to verify the numerical approach, results have been compared with the experimental data which shows a good agreement.

Heat Transfer in Processing and Use of Rubber

1967 ◽  
Vol 40 (1) ◽  
pp. 36-99 ◽  
Author(s):  
S. D. Gehman
Keyword(s):  
Heat Transfer ◽  
Mechanical Energy ◽  
Convection Heat Transfer ◽  
Internal Heat ◽  
Frictional Heat ◽  
Turbulent Heat Transfer ◽  
Temperature Sensitive ◽  
Turbulent Heat ◽  
Large Power ◽  
Power Inputs

Abstract Heat transfer in rubber is likely to be significant from the first processing steps to the end use of the product. At the start, it is encountered in preparing, drying, and handling raw polymers; then in mixing and forming or molding compounds. In this stage, the thermoplastic nature of rubber is such that viscosity and other physical characteristics are especially temperature sensitive. Heat is the most important processing agent. The rate at which heat can get into and out of rubber, how expertly it can be transferred, affects the design of processing machinery and controls the speed of many mixing, extruding, and molding operations. In these processes, primary, turbulent heat transfer between rubber and steel and mass transfer in the rubber are complicated by frictional heat generation at the rubber-metal surfaces and large conversion of mechanical energy into internal heat. Convection heat transfer with air, steam, or fluids also usually occurs in processing rubber. Localized overheating at any stage can be disastrous for quality. Hence the basic heat problems in processing usually lie in rapidly and efficiently securing, and then maintaining, satisfactory temperature uniformity in a material with inherently poor heat transfer characteristics. Dispersing fillers in rubber requires large power inputs but the resulting temperature rise must not be so great as to cause prevulcanization or reduce unduly the efficiency of the mixing operation by too great reduction in plasticity and hence shearing stresses. On the other hand, Hahn has pointed out how advantageous such mechanical heating of rubber may be. A few minutes working on a mill may accomplish more in raising the temperature than hours of conduction heat flow. After rubber is mixed and formed, vulcanization ensues with flow of heat to raise the temperature throughout to the vulcanization range and thus activate the chemical reactions of vulcanization. At this stage, control of heat is exceedingly important for costs and quality. Any shortening of the vulcanizing cycle without detriment to quality provides opportunity to increase productivity of a large capital investiment. Finally, heat is one of the most destructive agents for finished rubber products. It presents a frontier for development of new rubbers and applications. External environmental heat imposes service limitations and in dynamic uses involving repeated, rapid deformations internal transformation of mechanical energy into heat may readily destroy thick rubber sections.

Local Heat Transfer in a Rotating Two-Pass Triangular Duct With Smooth Walls

1994 ◽  
Author(s):  
Sandip Dutta ◽  
Je-Chin Han ◽  
Yuming Zhang ◽  
C. Pang Lee
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Cross Section ◽  
Rotation Number ◽  
Secondary Flows ◽  
Rate Of Change ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Earlier heat transfer studies with orthogonal rotation were conducted mostly on ducts of square cross-section. This paper reports a different cross-section, a triangular duct. Unlike a square cross-section, the triangular shape provides more restriction to the formation of the secondary flows. Moreover, the studied orientation of the right triangular duct avoids formation of symmetric vortex structures in the cross flow plane. This paper presents turbulent heat transfer characteristics of a two-pass smooth walled triangular duct. One pass is for radial outward flow and the other for radial inward flow. With rotation the radial outward and inward flow directions show different surface heat transfer characteristics. Like a square duct, differences between the trailing and the leading Nusselt number ratios for the triangular duct increase with rotation number. However, the rate of change of Nusselt number ratios with rotation number varies for the two duct geometries. Standard k-ε model predictions for a radial outward flow situation show that the Nusselt number ratio variations with Reynolds number are not drastic for the same rotation number.

Screening and Correlating Data on Heat Transfer to Fluids at Supercritical Pressure

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
J. Derek Jackson
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Convection Heat Transfer ◽  
Correlated Data ◽  
Supercritical Pressure ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Convection Heat ◽  
Fluid Properties ◽  
Ratio Correction

A simple criterion for screening experimental data on turbulent heat transfer in vertical tubes to identify those not significantly influenced by buoyancy was proposed by the author many years ago and found to work quite well for water and air at normal pressures. However, it was recognized even then that the ideas on which the criterion was based were too simplistic to be suitable for use in the case of fluids at supercritical pressure. With the passage of time and tremendous advancement in data processing capability using present-day computers, it is now possible to contemplate adopting a refined approach specifically designed to be suitable for such fluids. The present paper describes a semi-empirical model of buoyancy-influenced heat transfer to fluids at supercritical pressure, which takes careful account of nonuniformity of fluid properties. It provides a criterion for determining the conditions under which buoyancy influences are negligibly small. Thus, the extensive databases now available on heat transfer to fluids at supercritical pressure can be reliably screened to eliminate those affected by such influences. Then, the many correlation equations that have been proposed for forced convection heat transfer can be evaluated in a reliable manner. These equations mostly relate Nusselt number to Reynolds number, Prandtl number, and simple property ratio correction terms. Thus, they should be evaluated using only experimental data that are definitely not influenced by buoyancy. A further outcome of the present paper is that it might now prove possible to correlate the buoyancy-influenced data in such databases and fit the equation for mixed convection heat transfer yielded by the model to the correlated data. If this can be done, it will represent a major advancement in terms of providing thermal analysts with a valuable new tool.

Single-phase laminar and turbulent heat transfer in smooth and rough microtubes

2007 ◽  
Vol 3 (6) ◽  
pp. 697-707 ◽  
Author(s):  
G. P. Celata ◽  
M. Cumo ◽  
S. J. McPhail ◽  
G. Zummo
Keyword(s):  
Heat Transfer ◽  
Single Phase ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat
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