Skip to main content
SpringerLink
Log in

PIV measurement of internal flow characteristics of very low specific speed semi-open impeller

  • Original
  • Published:
Experiments in Fluids Aims and scope Submit manuscript

Abstract

Detailed particle-image velocimetry (PIV) measurements of flow fields inside semi-open impellers have been performed to understand better the internal flow patterns that are responsible for the unique performance of these centrifugal pumps operated in the range of very low specific speed. Two impellers, one equipped with six radial blades (impeller A) and the other with four conventional backward-swept blades (impeller B), are tested in a centrifugal pump designed to be operated at a non-dimensional specific speed of ns=0.24. Complex flow patterns captured by PIV are discussed in conjunction with the overall pump performance measured separately. It is revealed that impeller A achieves higher effective head than impeller B even though the flow patterns in impeller A are more complex, exhibiting secondary flows and reverse flows in the impeller passage. It is shown that both the localized strong outward flow at the pressure side of each blade outlet and the strong outward through-flow along the suction side of each blade are responsible for the better head performance of impeller A.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15
Fig. 16
Fig. 17
Fig. 18
Fig. 19
Fig. 20
Fig. 21

Similar content being viewed by others

Abbreviations

A 2 :

impeller outlet area, =2πr2b2

b :

impeller passage height (m)

c :

tip clearance (m)

C p :

pressure coefficient, =(p−ps)/(ρu22/2)

d p :

particle diameter (m)

f :

focal length (mm)

g :

acceleration of gravity (m/s2)

H :

effective head (m)

n :

rotational speed (rev/min)

n s :

non-dimensional specific speed

P :

pump power (W)

p :

static pressure measured at impeller outlet (Pa)

p s :

static pressure measured at pump suction area (Pa)

Q :

volume flow rate (m3/min)

Q 0 :

volume flow rate (m3/min) at the best efficiency point (BEP)

Q d :

designed flow rate (m3/min)

Re :

Reynolds number, =u2r2/ν

r :

impeller radius (m)

u :

tangential velocity of impeller (m/s)

u d :

drift velocity (m/s)

vr, v θ :

phase-averaged absolute radial and tangential velocities (m/s)

\( \overline{{v_{{\text{r}}} }} ,\overline{{v_{\theta } }} \) :

time-averaged (or ensemble-averaged) absolute radial and tangential velocities (m/s)

\( \overline{\overline {v_{{\theta 2}} }} \) :

periphery-averaged absolute tangential velocity at the impeller outlet (m/s)

z :

wall-normal distance from suction cover surface (m)

β :

blade angle

γ :

algebraic spiral angle of volute

η :

pump efficiency, =ρgQH/P×100 (%)

θ :

tangential angle measured from volute tongue

θ s :

tangential angle measured at the suction side of impeller blade

ν :

kinematic viscosity (m2/s)

ρ :

density of working fluid (kg/m3)

τ :

torque coefficient, \( = P/0.5\rho A_{2} u^{3}_{2} \)

φ :

discharge coefficient, =Q/A2u2

ψ :

head coefficient, \( = \frac{H} {{{u^{{\text{2}}}_{{\text{2}}} } \mathord{\left/ {\vphantom {{u^{{\text{2}}}_{{\text{2}}} } {2g}}} \right. \kern-\nulldelimiterspace} {2g}}} \)

ω :

angular velocity of impeller (rad/s)

2:

quantities at impeller outlet

References

  • Abramian M, Howard JHG (1994) Experimental investigation of the steady and unsteady relative flow in a model centrifugal impeller passage. J Turbomach 116:269–279

    Google Scholar 

  • Akin O, Rockwell D (1994) Flow structure in a radial flow pumping system using high-image-density particle image velocimetry. J Fluids Eng 116:538–544

    Google Scholar 

  • Aramaki S, Hayami H (1999) Unsteady flow measurement in a rotating impeller using PIV. In: Proceedings of the 3rd International Workshop on Particle image velocimetry, Santa Barbara, USA, Paper No. PIV108

  • Cao Z-M, Nishino K, Mizuno S, Torii K (2000) PIV measurement of internal structure of diesel fuel spray. Exp Fluids Suppl. S211–S219

  • Choi Y-D, Kurokawa J, Matsui J, Imamura H (2002) Internal flow characteristics of a centrifugal pump with very low specific speed. In: Proceedings of the 21st IAHR Symposium on Hydraulic machinery and systems, Lausanne, Switzerland, vol 1, pp 317–323

  • Dong R, Chu S, Katz J (1992) Quantitative visualization of the flow within the volute of a centrifugal pump (part A: technique). J Fluids Eng 114:390–395

    CAS  Google Scholar 

  • Dong R, Chu S, Katz J (1992) Quantitative visualization of the flow within the volute of a centrifugal pump (part B: results and analysis). J Fluids Eng 114:396–403

    CAS  Google Scholar 

  • Eisele K, Zhang Z, Casey MV (1997) Flow analysis in a pump diffuser (part 1: LDA and PTV measurements of the unsteady flow). J Fluids Eng 119:968–977

    CAS  Google Scholar 

  • Gorbis ZR, Spokoyny FE (1995) Momentum and heat transfer in turbulent gas–solid flows. Begell House, pp 1–8

  • Kurokawa J, Matsumoto K, Matsui J, Kitahora T (1998) Performances of centrifugal pumps of very low specific speed. In: Proceedings of the 19th IAHR Symposium on Hydraulic machinery and cavitation, Singapore, vol 2, pp 833–842

  • Kurokawa J, Matsumoto K, Matsui J, Imamura H (2000a) Development of high efficiency volute pump of very low specific speed. In: Proceedings of the 6th Asian International Conference on Fluid machinery, Johor, Malaysia, pp 250–255

  • Kurokawa J, Matsumoto K, Matsui J, Imamura H (2000b) Performance improvement and peculiar behavior of disk friction and leakage in very low specific-speed pumps. In: Proceedings of the 20th IAHR Symposium on Hydraulic machinery and cavitation, Charlotte, USA, CD-ROM PD-02

  • Matsui J, Choi Y-D, Kurokawa J, Imamura H, Hara M (2002) Internal flow in a centrifugal pump of a low specific speed with semi-open impeller (in Japanese). Trans JSME 68B (668):1174–1180

    Google Scholar 

  • Minemura K, Kinoshita K, Ihara M, Egashira K (1995) Effects of design parameters on air–water two-phase flow performance of a radial-flow pump (in Japanese). Trans JSME 61B (588):2996–3004

    Google Scholar 

  • Murakami M, Kikuyama K, Asakura E (1980) Velocity and pressure distributions in the impeller passages of centrifugal pumps. J Fluids Eng 102:420–426

    Google Scholar 

  • Ohta H, Aoki K (1990) Study on centrifugal pump for high-viscosity liquids (effect of impeller blade number on the pump performance) (in Japanese). Trans JSME 56B (644):1702–1707

    Google Scholar 

  • Paone N, Riethmuller ML, Van den Braembussche RA (1989) Experimental investigation of the flow in the vaneless diffuser of a centrifugal pump by particle image displacement velocimetry. Exp Fluids 7:371–378

    CAS  Google Scholar 

  • Rodgers C (1990) Experiments with a low-specific-speed partial emission centrifugal compressor. J Turbomachinery 112:30–37

    Google Scholar 

  • Stepanoff A (1957) Centrifugal and axial flow pumps, 2nd edn. Wiley, New York, pp 69–89

  • Tsukiya T, Akamatsu T (1997) Fluid dynamic design of Kyoto-NTN magnetically suspended centrifugal blood pump. ASME FEDSM 97, FEDSM97-3425:1–6

    Google Scholar 

  • Worster RC (1963) The flow in volutes and its effects on centrifugal pump performance. Proc Inst Mech Eng 177(31):843–875

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Mechanical Engineering, Graduate School of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, 240-8501, Yokohama, Japan

    Y.-D. Choi, K. Nishino, J. Kurokawa & J. Matsui

Authors
  1. Y.-D. Choi
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. K. Nishino
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. J. Kurokawa
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. J. Matsui
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Y.-D. Choi.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Choi, YD., Nishino, K., Kurokawa, J. et al. PIV measurement of internal flow characteristics of very low specific speed semi-open impeller. Exp Fluids 37, 617–630 (2004). https://doi.org/10.1007/s00348-004-0838-7

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00348-004-0838-7

Keywords

Search

Navigation