International Journal of Multiphase Flow 37 (2011) 1305–1314

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International Journal of Multiphase Flow

journal homepage: www.elsevier .com/ locate / i jmulflow

Experimental and numerical analysis of steam jet pump

Ajmal Shah a,⇑, Imran Rafiq Chughtai b, Mansoor Hameed Inayat b

a Department of Nuclear Engineering, Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad, Pakistanb Department of Chemical Engineering, Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad, Pakistan

a r t i c l e i n f o

Article history:Received 23 May 2011Received in revised form 21 July 2011Accepted 30 July 2011Available online 22 August 2011

Keywords:Steam jet pumpCFDDirect-contact condensationCondensation model

0301-9322/$ - see front matter � 2011 Elsevier Ltd. Adoi:10.1016/j.ijmultiphaseflow.2011.07.008

⇑ Corresponding author. Tel.: +92 51 2207381x346fax: +92 51 2208070.

E-mail addresses: ajmal@pieas.edu.pk (A. ShahChughtai), mansoor@pieas.edu.pk (M.H. Inayat).

a b s t r a c t

Steam jet pump is the best choice for pumping radioactive and hazardous liquids because it has no mov-ing parts and so no maintenance. However, the physics involved is highly complicated because of themass, momentum and energy transfer between the phases involved. In this study the characteristics ofSJP are studied both experimentally and numerically to pump water using saturated steam. In the exper-imental study the static pressure, temperature along the length of the steam jet pump and the steam andwater flow rates are recorded. The three dimensional numerical study is carried out using the Euleriantwo-phase flow model of Fluent 6.3 software and the direct-contact condensation model developed pre-viously. The experimental and CFD results, of axial static pressure and temperature, match closely witheach other. The mass ratio and suction lift are calculated from experimental data and it is observed thatthe mass ratio varies from 10 to 62 and the maximum value of suction lift is 2.12 m under the conditionsof the experiment.

� 2011 Elsevier Ltd. All rights reserved.

1. Introduction

Steam jet pump (SJP) is a device which uses steam to pump liq-uids, gases or a mixture of liquids, gasses and/or solids. In thesepumps a high velocity jet of the motive medium (steam) is producedthrough converging–diverging nozzles to create vacuum and en-train the medium to be pumped. Steam jet pump has several advan-tages over the conventional pumps like it has no moving parts, noexternal power required, low maintenance, simple compact andeasy to install. These features have made steam jet pump very attrac-tive for creating suction and pumping hazardous liquids in variousindustries. The jet pump has been used as feedwater supply devicein locomotives and merchant marines and as a steam jet air ejectorfor de-aeration of the turbine condensers. It is also used in the oil andgas industry for increasing their production (Conti et al., 1993; Ash-ton et al., 1993; Villa et al., 1997) and in the desalination of water(Senthil Kumar et al., 2003, 2004, 2005). The performance of steamjet pump is analyzed by Yan et al. (2005) for district-heating. As a re-sult of his experimental and theoretical calculations he concludedthat steam jet pump can be used effectively for district-heating. Inthe past two decades, steam jet pump is studied both experimentallyand computationally by a number of researchers (Aybar and Bei-thou, 1999; Beithou and Aybar, 2000, 2001a,b; Cattadori et al.,1995; Deberne et al., 1999; Dumaz et al., 2005; Narabayashi et al.,

ll rights reserved.

1; mobile: +92 346 5006305;

), imran@pieas.edu.pk (I.R.

1997, 2000) and proposed that steam jet pump can be used for emer-gency core cooling and feedwater supply system in advanced nucle-ar reactors.

A two dimensional sketch of steam jet pump is shown in Fig. 1.It can be divided into the following four parts.

1.1. Steam nozzle

It has a typical converging–diverging shape and its function is toaccelerate the motive steam to sonic or supersonic speed. Thesteam expands nearly isentropically through the steam nozzleand its enthalpy is partly converted into the kinetic energy, result-ing in high speed flow.

1.2. Water nozzle

The space around the steam nozzle leading to the mixing sec-tion is called the water nozzle. Its function is to produce moderateacceleration and distribute the water all around the exit of thesteam nozzle.

1.3. Mixing section

This section is in the shape of a converging nozzle, where, thetwo streams (steam from steam nozzle and water from waternozzle) come in direct contact with each other. The mixing sectionmay be considered as the heart of the steam jet pump because allthe thermodynamic processes and the suction and pumping char-acteristics of SJP depend on the transport phenomena occurring in

Fig. 1. Schematic of steam jet pump (all dimensions are in mm).

1306 A. Shah et al. / International Journal of Multiphase Flow 37 (2011) 1305–1314

this section. An interface is developed between the two phases inthe mixing section and the mass, momentum and energy transferbetween them occurs across this interface. As a result of the masstransfer due to condensation of steam the end result is subcooledwater at relatively high pressure.

1.4. Diffuser

The last section of steam jet pump is called the diffuser and itsfunction is to increase further the pressure of outgoing water. It hasa diverging shape.

Mechanically steam jet pump is the simplest type of all thepresent-day vacuum pumps and compressors. However, the ther-mal hydrodynamic phenomena producing the suction and pump-ing action is highly complex and technically sophisticated. Thetechnology of steam jet pump has been known for more than acentury but due to the above mentioned complexity of the pro-cesses involved, it is not as common in use as it should be. How-ever, with the evolution of computers and computational fluiddynamics it is now the time to understand the physics of SJP.

In this work it is aimed to study, experimentally, the character-istics of a lab scale steam jet pump at various operating conditionsand to simulate the thermal hydrodynamic phenomena occurringwithin such pumps using three dimensional numerical analyses.The simulations are carried out using commercial software Fluent6.3 and the direct-contact condensation of steam into subcooledwater is modeled using the condensation model presented by Shahet al. (2010). The experimental study will help in understanding

Fig. 2. Block diagram of the

the performance of SJP and validating the computational results.On the other hand numerical study will help in understandingthe physics of the direct contact condensation and will give a thor-ough insight of the processes involved.

2. Experimental system

The experimental system of steam jet pump is shown in Fig. 2. Itconsists of a steam boiler, steam jet pump, data acquisition sys-tems, a computer, water tanks, pressure transmitters and gauges,thermocouples and other associated equipments for flow controland measurement. The steam boiler has a power of 36 kW andits tank capacity is 38 l. It can give a maximum flow rate of52 kg/h at a maximum operating pressure of 8 bars. It supplied sat-urated steam continuously during the experiment. Temperature ismeasured by K type thermocouples with an accuracy of 1 �C. Pres-sure is measured by pressure transmitters model ‘PCE-28’ of Apli-sens brand having accuracy of 0.2% over the operating range. Twodata acquisition systems (Iotech data acquisition system, model‘personnel DAQ 3000 series’ and Pico data logger) are used, onefor measuring the static pressure and the other for measuring tem-perature at eight different locations along the length of the steamjet pump. The suction pressure at water nozzle is measured withthe help of a pressure transmitter model, ‘626-00C-CH-P1-E5-S1-LED’ of Dwyer brand. It measures the suction pressure in inchesof mercury with an accuracy of 0.25%. The steam jet pumpgeometry is made of brass material in three separate parts: (i)the steam nozzle, (ii) the water nozzle and (iii) the mixing section

experimental system.

Table 1The parameters of steam, water and geometric configuration.

Steam inlet pressure, Psa (kPa) 140–220Steam inlet temperature, Tsa (K) 382–396Water inlet pressure, Pw (kPa) 96Water inlet temperature, Tw (K) 290Ambient pressure, Pam (kPa) 96Steam nozzle throat diameter, Db (mm) 6.10Steam nozzle outlet diameter, Dsc (mm) 7.12Water nozzle outlet diameter, Dwc (mm) 24.0Mixing section throat diameter, Dd, De (mm) 15.5Diffuser outlet diameter, Df (mm) 30.0Steam nozzle length, Lac (mm) 50.0Mixing section length, Lce (mm) 110.0Diffuser length, Lef (mm) 100.0Total length, L (mm) 260.0

Table 2The uncertainty in experimental data.

Measurement Range Uncertainty (%)

Mass flow rate 0.006–0.98 kg/s 3.3Pressure 80.76–220.0 kPa 4.0Temperature 290–396 K 6.7Diameter 6.1–30.0 mm 4.8

A. Shah et al. / International Journal of Multiphase Flow 37 (2011) 1305–1314 1307

and diffuser. The steam nozzle is designed based on the one dimen-sional compressible flow theory to produce supersonic or at leastsonic flow at the exit of the steam nozzle at the operating condi-tions of the steam. The parameters of steam, water and geometricalconfiguration used are listed in Table 1. The experimental uncer-tainty in mass flow rate, pressure, temperature and diameter isdetermined using the model of Moffat (1982). The range anduncertainty in the above mentioned parameters are listed in Table2. The uncertainty results include the effects of observed scatter inmeasured data and the reported accuracy of the instruments usedfor measurements.

It is possible to independently vary the inlet steam pressure,water nozzle suction pressure and water back pressure. Theparameters measured during the experiment are given below.

� The inlet and outlet flow pressure and temperature.� The pressure and temperature along the length of the SJP.� The inlet and exit mass flow rates.

3. Mathematical model

Three dimensional, compressible, two phase Eulerian model isused for simulating the flow of SJP. In this model each phase hasits separate set of momentum, continuity, and energy equationsand the coupling between the phases is achieved through pressureand the interphase exchange coefficients. The realizable k–e modelis used to model the turbulence characteristics of the flow. At theinterface the process of direct-contact condensation is modeledusing the condensation model of Shah et al. (2010), while the sym-metric model is used for drag formulation between the phases. Abrief description of multiphase Eulerian model and the condensa-tion model is given below while, the details of the other modelscan be found in Fluent (2006), Ranade (2002), and Shah et al.(2010).

3.1. Eulerian model

Eulerian multiphase flow model solves the volume fraction,mass, momentum and energy equations for each phase. Theseequations for phase q and exchanging mass with phase p are givenbelow.

Vq ¼Z

VaqdV ð1Þ

Xn

q¼1

aq ¼ 1 ð2Þ

@

@tðaqqqÞ þ r � ðaqqqmqÞ ¼

Xn

p¼1

ð _mpq � _mqpÞ þ Sq ð3Þ

@

@tðaqqqmqÞ þ r � ðaqqqmqmqÞ ¼ �aqrP þr � sq þ aqqqg

þXn

p¼1

ðRpq þ _mpqmpq � _mqpmqpÞ

þ Fq þ F lift;q þ Fmm;q ð4Þ

@

@tðaqqqhqÞ þ r:ðaqqquqhqÞ ¼ �aq

@Pq

@tþ sq

: ruq �rqq þ Sq þXn

p¼1

ðQ pq

þ _mpqhpq � _mqphqpÞ ð5Þ

Vq, aq, qq, mq, Sq, sq and hq are the volume, volume fraction, density,velocity, source term, stress–strain tensor and enthalpy of the qthphase. While, _mpq, _mqp, hpq, hqp, Fq, Flift,q, Fmm,q, Rpq, qq and Qpq arethe interphase mass transfer terms, interphase enthalpies, externalbody force, lift force, virtual mass force, phases interaction force,heat flux and the source term including sources of enthalpy. The de-tails of terminologies involved in these equations are given inFluent (2006), Ranade (2002), and Shah et al. (2010).

3.2. Condensation model

The condensation model presented by Shah et al. (2010) is usedto model the direct-contact condensation between the steam andwater. A brief introduction of the model is given here.

The rate of energy transfer during the process of direct-contactcondensation is based on three key parameters: interfacial area,interfacial heat transfer coefficients and interfacial mass transfer.

3.2.1. Interfacial areaSpecification of volumetric heat transfer coefficients requires an

estimate of the interfacial area per unit volume (Afg). For sphericalvapor bubbles of diameter dg and with the volume fraction ag in aliquid, the interfacial area per unit volume is estimated by

Afg ¼6ag

dgð6Þ

The mean bubble diameter dg is modeled by Anglart and Nylund(1996) and Kurul (1990) as a linear function of local liquid subcool-ing (Ts � Tf) and its relation is given in Anglart and Nylund (1996),Kurul (1990), and Shah et al. (2010). Ts, and Tf are the local vaporand liquid temperatures.

3.2.2. Interfacial heat transfer coefficientsThe heat transfer coefficients between fluids are required to

perform the heat and mass transfer calculations. The heat transferbetween the two fluids was modeled in two steps: (i) from vapor tothe interface and (ii) from interface to the liquid. Thus the heattransfer phenomena in direct-contact condensation is character-ized by two heat transfer coefficients one on the vapor side andthe other on the liquid side of the interface (Shah et al., 2010).The model has the following assumptions:

1308 A. Shah et al. / International Journal of Multiphase Flow 37 (2011) 1305–1314

� The interface is assumed to be at saturation conditions at thelocal pressure.� Vapor is assumed superheated or at least saturated.� Liquid is assumed subcooled or at the most saturated.� Condensation is assumed to occur at saturation conditions.

The liquid phase heat transfer coefficient hf is related to theNusselt number Nuf, thermal conductivity of liquid kf and dg by:

hf ¼kf Nuf

dgð7Þ

The Nuf is calculated using the correlation of Hughmark (1967)as given below:

Nuf ¼2:0þ 0:6Re0:5Pr0:33; 0 6 Re < 776:06; 0 6 Pr < 2502:0þ 0:27Re0:62Pr0:33; 776:06 6 Re; 0 6 Pr < 250

(

ð8Þ

Re and Pr are the relative Reynolds number and Prandtl number ofthe liquid. Their relations are given in Shah et al. (2010).

The volumetric heat transfer coefficient Hf for liquid phase is

Hf ¼ hf Afg ð9Þ

A large heat transfer coefficient on the vapor side of the inter-face hg is assumed to bring the vapor temperature quite close tothe saturation temperature (Brucker and Sparrow, 1977; Shahet al., 2010).

hg ¼ 104 Wm2 � K

ð10Þ

Hg ¼ hgAfg ð11Þ

Hg represents the volumetric heat transfer coefficient on the vaporside.

3.2.3. Interfacial mass transferAccurately modeling the interfacial mass transfer is very impor-

tant in direct-contact condensation process, because the transfer ofmass accompanies the transfer of heat and momentum. The rate of

Fig. 3. Meshed geometry of SJP, (A) full geometry showing external surface

energy transfer from interface to liquid qf is assumed to be a func-tion of local liquid subcooling:

qf ¼ hf ðTs � Tf Þ ð12Þ

Similarly, the rate of energy transfer from vapor to interface qg

is given by

qg ¼ hgðTs � TgÞ ð13Þ

The heat flux from the interface to the liquid phase Qf and fromthe vapor phase to interface Qg are given by

Qf ¼ �qf � _mfgHfs ð14Þ

Qg ¼ �qg þ _mfgHgs ð15Þ

The interphase mass transfer _mfg is derived from the total heatbalance.

_mfg ¼qf þ qg

Hgs � Hfsð16Þ

Hgs and Hfs are the saturation enthalpies of vapor and liquid phases.

4. Numerical simulation

Three dimensional steady state analyses are carried out to sim-ulate the steam-water two phase compressible and supersonicflow inside a steam jet pump. Eulerian model is used forsimulation, in which different phases are treated as interpenetrat-ing continua. Fluent 6.3 software is used for the simulation. Thedirect-contact condensation of steam into subcooled water is mod-eled using the condensation model of Shah et al. (2010) and isembedded in the Fluent code as ‘User Defined Function’. The steamis treated as a compressible fluid using the ideal gas relation. Theideal gas relation seems to be the idealistic assumption to the mod-el, it is proved by Aphornratana (1994) that it provides similar re-sults to a real gas model. It is also used by Shah et al. (2010) andSriveerakul et al. (2007) for the simulation of such flows. As theflow is supersonic and compressible it is expected to be highly tur-bulent, the realizable k–e model is used. The symmetric model for

mesh, (B) enlarged and sectioned view showing internal surface mesh.

Table 3Boundary values used in CFD simulation.

Steam inlet pressure, Psa (kPa) 140, 160, 180, 200, 220Steam inlet temperature, Tsa (K) SaturatedWater nozzle pressure, Pwc (kPa) 93.56, 92.92, 91.87, 90.38, 89.30Water nozzle temperature, Twc (K) 290Water exit pressure, Pwf (kPa) 96

A. Shah et al. / International Journal of Multiphase Flow 37 (2011) 1305–1314 1309

drag force available in Fluent 6.3 software is used for the evalua-tion of drag function. SIMPLE coupled-implicit solver is used tosolve the non-linear governing equations. Power law scheme isused for discretization of all the equations except the continuityand volume fraction equations. For these two equations the secondorder and first order upwind scheme are used respectively. Thealgebraic multigrid solver is used which performs calculations onfiner mesh and no coarse meshes have to be constructed or stored,and no fluxes or source terms need to be evaluated on the coarselevels.

The steam and water inlets are selected as the inlet pressureboundaries and the outlet of the SJP is selected as the outlet pres-sure boundary, while the walls of SJP are taken as adiabatic wallboundaries. The values of viscosity, thermal conductivity and spe-cific heat capacity of steam are taken from fluent database and areassumed constant during the simulation. The same treatment of

Fig. 4. Static pressure along the length of SJP,

vapor properties is used by Sriveerakul et al. (2007) in the simula-tion of steam jet ejector.

The geometry and mesh are generated in Gambit 2.2.30 soft-ware. A total of 69,677 cells of hexahedral and tetrahedral shapeare generated inside the SJP geometry. The meshed geometry ofSJP is shown in Fig. 3. The minimum cell volume is 0.1 mm3 andthe maximum cell volume is 24.3 mm3.

The experimental results of five cases are used as boundary con-ditions to perform their simulation. The details of the boundaryvalues of these five cases are given in Table 3.

5. Results and discussions

In this work the steam jet pump is studied both experimentallyand computationally to validate the model of Shah et al. (2010) fordirect-contact condensation and to study the characteristics of SJP.The parameters studied are discussed below.

5.1. Flow static pressure and temperature

The flow static pressure along the length of the SJP is measuredexperimentally and computed numerically for the five casesmentioned in Table 3. These results are shown in Fig. 4. The steam

h: Experimental results, d: CFD results.

1310 A. Shah et al. / International Journal of Multiphase Flow 37 (2011) 1305–1314

pressure decreases in the steam nozzle due to expansion and theresult is supersonic flow and negative gauge pressure at the exitof the steam nozzle (Fig. 4). The negative pressure at the exit ofthe steam nozzle creates a negative pressure at the exit of thewater nozzle. The pressure difference between the water tankand the water nozzle results in suction of water. The numerical re-sults of Fig. 4 show that a shock wave appears at the entrance ofthe mixing section. This shock is also reported by Beithou and Ay-bar (2001b) and Cattadori et al. (1995) and has a negative effect onthe suction capacity of the SJP. The pressure in the converging partof mixing section is nearly constant for all cases (Fig. 4A–E). Beforethe end of mixing section the steam is fully condensed and due tocompression wave the pressure rises. The pressure further in-creases in the diffuser (Fig. 4).

Like static pressure the axial flow temperature is measuredexperimentally along the length of SJP and computed numericallyas a result of CFD simulations. The results are shown in Fig. 5. Inthe steam nozzle temperature decreases due to steam expansion,however, it first increases due to shock wave at the entrance ofmixing section and then decreases due to condensation and mixingwith the subcooled water. At the end of the mixing sectioncondensation is complete and the temperature remains constant

Fig. 5. Flow temperature along the length of SJ

in the diffuser. The CFD results of static pressure and temperaturematch closely with the experimental results (Figs. 4 and 5) andthus support the simulations.

5.2. Mass ratio and water flow rate

Mass ratio is an important parameter to study the performanceof SJP. It is defined as the ratio of sucked water to the inlet steammass flow rate. It represents the amount of sucked water per unitof steam consumed. In the experimental work the water tank at thesuction side is at atmospheric pressure of 96 kPa and the water le-vel in the tank is maintained at a depth of one foot from the waternozzle of the SJP. The water nozzle exit pressure is varied by avalve between the water tank and the water nozzle. It is observedduring the experiments that at a given steam pressure closing thevalve gradually, the water mass flow rate decreases and the nega-tive pressure at the water nozzle exit increases or it can be statedthat mass ratio is inversely proportional to the negative pressure atthe water nozzle exit provided that steam pressure is constant. An-other important observation made is that increasing the steam in-let pressure causes the negative pressure to increase provided thevalve position is not changed or it can be stated that mass ratio is

P, h: experimental results, d: CFD results.

A. Shah et al. / International Journal of Multiphase Flow 37 (2011) 1305–1314 1311

directly proportional to the steam inlet pressure provided thatvalve position is not changed.

Fig. 6 shows the experimental result of mass ratio as afunction of the negative pressure at the water nozzle exit andsteam inlet pressure and supports the above discussion. The massratio varies in the range of 10–62 under the conditions in thisexperiment. The suction water mass flow rate as a function ofsteam inlet pressure and water nozzle negative pressure is shownin Fig. 7. The water mass flow rate increases with increasing thesteam inlet pressure provided the water nozzle negative pressureis kept constant. The reason is that, while increasing the steampressure, constant suction pressure at water nozzle can be main-tained only by opening the valve gradually or in other words byreducing the head loss in the valve. On the other hand the waterflow rate decreases with increasing the negative suction pressureprovided the steam pressure is kept constant. The reason is obvi-ous that the negative pressure increases by closing the valve at aconstant steam pressure.

Fig. 6. Mass ratio of

Fig. 7. Suction water mass flow

5.3. Suction lift

The available literature studies SJP as an injector or ejector,mainly. In injectors the back pressure higher than the steam inletpressure is achieved and the suction water pressure is generallyhigher than the atmospheric pressure. While, in ejectors the flowis generally single phase. However, in this work it is aimed to studySJP as a pumping device to suck water from a tank at atmosphericpressure and at a certain depth.

Suction lift is defined as the theoretical variable depth fromwhich the SJP is able to suck water under different operating con-ditions. In order to calculate the suction lift the Bernoulli’s equa-tion is applied between the water tank and the exit of waternozzle. The water tank is at an atmospheric pressure of 96 kPaand the exit pressure of water nozzle is measured during theexperiment at different steam pressures. The Bernoulli’s equationapplied between the water tank and the exit of water nozzle,neglecting the friction losses in the piping, is given below.

steam jet pump.

rate of steam jet pump.

Fig. 8. Suction lift of steam jet pump.

Fig. 9. CFD results of volume fraction.

1312 A. Shah et al. / International Journal of Multiphase Flow 37 (2011) 1305–1314

Pw

qwgþ 0:5

m2w

gþ zw ¼

Pwc

qwagþ 0:5

m2wc

gþ zwc ð17Þ

zwc ¼Pw � Pwc

qwg� 0:5

m2wc

gþ zw ð18Þ

mwc ¼mw

qwAwcð19Þ

where the first subscript of the parameters used in the above equa-tions, ‘w’ represents water and the second subscript ‘c’ representsthe section ‘c’ mentioned in Fig. 1. ‘Z’ is the potential head.

Fig. 10. CFD results of interfacial mass transfer (condensation interface).

Fig. 11. CFD results of steam velocity in steam nozzle and mixing section.

A. Shah et al. / International Journal of Multiphase Flow 37 (2011) 1305–1314 1313

Fig. 8 shows the suction lift as a function of steam pressure andsuction pressure at the water nozzle exit. Increasing the negativesuction pressure of water, increases the suction lift provided thesteam pressure is kept constant. However, increasing the steampressure causes the suction lift to decrease provided the suctionpressure is kept constant the reason is that at high steam pressurethe steam nozzle exit pressure increases thus reducing the pres-sure difference between the water nozzle and the mixing section.

However, It is observed that keeping the valve position unchangedand increasing the steam pressure actually, results in increasingthe negative suction pressure that’s why higher values of suctionlift are possible at high steam pressure.

5.4. Simulation results of volume fraction condensation interface andsteam velocity

The simulation results of the volume fraction, condensationinterface and steam velocity are shown in Figs. 9–11 at a steam in-let pressure of 160 and 200 kPa. The steam leaving the steam noz-zle forms a steam plume in the mixing section, which issurrounded by the entrained subcooled water in the annular spacebetween the steam plume and the wall of mixing section (Fig. 9).Therefore, an interface is formed between the saturated steamand the subcooled water in the mixing section (Fig. 10). The steamis fully condensed within the mixing section and the flow is singlephase as it leaves the mixing section. The compressible flow theorysuggests that there will be periodic expansion and compressionwaves in the steam plume (Shah et al., 2010; Wu et al., 2009,2010, 2007). These expansion and compression waves are clearlyvisible in Figs. 9 and 10.

The steam velocity increases in the steam nozzle and reaches itsmaximum value (supersonic) at the exit of the steam nozzle(Fig. 11). In the mixing section the steam comes in direct-contactwith subcooled water and there occurs a transfer of heat (due totemperature difference), momentum (due to velocity difference)and mass (due to condensation). Due to high velocity of steamthere is not enough time for heat transfer to occur between thetwo phases. However, due to momentum and mass transfer the

1314 A. Shah et al. / International Journal of Multiphase Flow 37 (2011) 1305–1314

steam velocity decreases sharply in the mixing section as shown inFig. 11. The effect of expansion and compression waves can also befelt in Fig. 11.

6. Conclusion

A lab scale steam jet pump is studied both experimentally andnumerically to access its suction characteristics and to validate themodel of direct-contact condensation of Shah et al. (2010). Thestudy includes;

1. The static pressure and temperature are measured experimen-tally along the length of SJP and compared with the CFD results.The two results are in close agreement with each other.

2. The mass ratio of steam jet pump is calculated from experimen-tal data and plotted as a function of steam pressure and waternozzle exit pressure. It varies in the range of 10–62 under theconditions of the experiment.

3. The suction lift is calculated from the experimental data and itis found that the SJP is able to suck water from a maximumdepth of 2.12 m under the conditions of the experiment.

4. The simulation results of volume fraction, condensation inter-face and steam velocity are plotted and discussed.

The agreement between the experimental and CFD results sup-port CFD simulation and condensation model of Shah et al. (2010).The experimental and simulation results of static pressure, tem-perature, mass ratio, suction water mass flow rate, suction lift, vol-ume fraction, condensation interface, and steam velocity providevaluable knowledge about steam jet pump.

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