1. NUMERICAL INVESTIGATION OF JET
PUMP WITH TWISTED TAPES
Arpita Srivastava Shaligram Tiwari and Mani Annamalai
Department of Mechanical Engineering
Indian Institute of Technology
Chennai, Tamil Nadu, India

2. Contents
 Introduction
 Literature survey
 Basic geometry of Jet Pump
 Tape description
 Results and discussion
 Conclusions
 References

3. Introduction
 Jet pump is used to transfer momentum from
a high velocity primary stream to a secondary
stream that gets entrained. It is packaged
with the advantage of geometrical simplicity
without any moving parts.
 Aim of the present study is to carry out three-
dimensional numerical investigations of two
phase flow jet pump in presence of twisted
tapes under optimized conditions of the
parameters such as upstream and
downstream pressures, primary jet mass flow
rate, entrained secondary stream mass flow
rate, geometry of the ejector, etc.

4.  Water and air have been used as fluids in the
primary and secondary streams respectively.
Nozzle profiles selected is conical. The mean
diameter of nozzles are kept to be 4mm and
6mm.
 Results in present study suggest that the
momentum exchange achieved by the swirl
causes increase in the efficiency of the jet
pump.

5. Literature Survey
 Sharma in his work experimentally verified that,
for lower area ratio, nozzles having elliptical
profile are capable of producing higher efficiency
then nozzles with circular or conical profile. He
experimented with different area ratio of nozzle.
The geometrical design for the present study is
taken from Sharma’s experiment.
 Hansen and Kinnavy performed experiments on
ejectors keeping different area ratio and then
studied different parametric effect. It was
concluded that area ratio has major role to play
in ejector efficiency than any other parameter.
 Abdus Samad investigated the influence of the
introduction of swirl low performance of an
ejector and concluded that it enhance the jet
breakup resulting in higher suction rates at
different optimized swirl angles.

6. Basic geometry of Jet Pump

7. Tape description

8. Pictorial representation of double
twisted tape incorporated in primary
nozzle

9. Numerical treatment the problem
 For the present study CFD software
ANSYS Fluent is used
 This code solves the discretized
equations in a segregated manner, with
SIMPLE algorithm.
 The first-order upwind scheme is taken
for momentum, volume fraction, turbulent
Kinetic energy and turbulent dissipation
rate discretisation.
 The solutions were assumed to have
converged for the residual level of 10-4
for continuity, x-velocity, and y velocity
and 10-6 for k -epsilon.

10.  For performing the grid study,
geometries with mesh size of
167231cells, 257111 cells, 430017 cells
707808 cells, 864906 cells, 1072648
cells and 1755598 cells were numerically
analyzed.
 Minimum orthogonal quality was kept at
0.5.The grid size was optimized by head
difference. It was observed that for the
geometries with higher mesh size,
variation in head difference was almost

11.  Since after 7.8lakhs grid size there was
no such significant difference in pressure
contours this was fixed as grid size for all
the further simulations which include
swirl generators also.
 Boundary conditions used for each
simulation are known static absolute
pressure.
 Turbulent intensity was selected 5 % and
respective hydraulic diameters were
used at each of the flow boundaries.

12. Results and Discussion
 On performing numerical studies, the ejector
incorporating double twisted tape is found to be highly
efficient comparatively to other ejector combination.
 It is also found that single twisted tape has the lesser
efficiency than double twisted tape but better than
without tape.
 The Table 2.shows the comparative parametric studies
carried out along with performance obtained.
 The velocity, turbulent kinetic energy and vorticity
magnitude graphs have been plotted against the
length of the ejector
 Efficiency of this arrangement is increased by 10%
when compared with nozzle, without any tape.

13. Comparison Of Various
Operating Parameters And
Performance

14. Velocity profiles for jet pump with
different twisted tape

15. Turbulent kinetic energy profiles
for jet pump with different twisted
tape

16. Vorticity magnitude profiles for jet
pump with different twisted tape

17. Velocity contours at the mid
plane for different Jet pumps

18. Conclusions
 It has been observed that there is a
change in flow behavior after the
nozzle when twisted tapes are
inserted in the upstream primary fluid
and more pressure drops after the
nozzle is observed due to high
vorticity magnitude. This enhances the
volume flow rate of the secondary air
which ultimately results in better
entrainment.

19. REFERENCES
 Pfleiderer, C., “Experiments on jet pump for its performance”, C.
Zeit, VDI, 58, 965 &1011.
 Martinelli, R.C., Boelter, L. M. K., Morrin, E. H., “Theoretical and
experimental analysis of ejectors Trans. ASME, 66, pp. 139-151.
 Senthil Kumar, R., Mani, A., Kumaraswamy, S. 2004, “Selection
of Pumps for Vacuum Desalination System Utilizing Ocean
Thermal Energy, 31st National Conference on Fluid Mechanics
and Fluid Power, Vol. 1, pp. 409–416.
 Senthil Kumar, R., Mani,A., Kumaraswamy, S., 2007,
“Experimental Investigation on Two-Phase Jet Pump used in
Desalination System ” , Desalination, 204, pp. 437-447.
 Hansen, A. G., and Kinnavy, R. 1965, “The design of water jet
pumps part I – experimental determination of optimum design
parameters”. ASME Paper 65-WA/FE-31.
 Riffat, S. B., Gan, G., and Smith, S., 1996, Computational fluid
dynamics applied to ejector heat pumps, Journal of Applied
Thermal Engineering, 16, 291-297.
 Riffat, S. B., and Omer, S. A. 2001, CFD modeling and
experimental investigations of an ejector refrigeration system,
Int. Journal on Energy Research, 25, 115-128.

20. Contd.
 Bartosiewicz, Y., Aidoun, Z., Mercadier, Y., 2006, “Numerical
assessment of ejector operation for refrigeration applications
based on CFD”, Applied Thermal Engineering, n 26, pp.604–
612.
 Sharma, V. Kumar., Kumaraswamy, S., Mani, A. 2012, “Effect
of Various Nozzle Profiles on Performance of a Two Phase
Flow Jet Pump”. Int. Journal of Mechanical and Aerospace
Eng,6, p.136-142.
 Samad, A., Omar, R., Hewakandamby, B., Lowndes I., and
Short, G. 2012, “Swirl Induced Flow Through a Venturi-
Ejector,” ASME 2012 Fluids Engineering Division Summer
Meeting (FEDSM2012), Puerto Rico, USA.
 Neve, R. S. 1993, “Computational fluid dynamics analysis of
diffuser performance in gas-powered jet pumps”, Int. Journal
on Heat and Fluid flow, 14, 401-407.
 Ouzzane, M., and Aidoun, Z. 2003, Model development and
numerical procedure for detailed ejector analysis and design,
Journal of Applied Engineering, 23, 2337-2351.

21. Thank you