Centrifugal Pump Working
Centrifugal Pump Working

centrifugal pumps are most commonly used turbomachinery devices which are used to raise pressure or induce flow in the control volume they are radial flow devices various kinds of centrifugal pumps are available in market with different construction details but working principle behind all of them remain same in this video we will analyze working principle of a centrifugal pump with single suction semi-open impeller one of such pump is shown in Figure with one part of its casing removed for ease of understanding working of centrifugal pump is simple as the impeller rotates it sucks fluid from outside through I of impeller the fluid is pushed radially along the impeller to the casing casing collects the fluid and it is pumped out through discharge nozzle we will go through main components of a centrifugal pump in a detailed way first impeller impeller is the device which rotates and transfer energy to fluid it has got collection of vanes fitted to a hub plate next component is casing which collects fluid from impeller in an efficient way the casing has got a special shape with area of cross-section increases from Inlet to outlet as the impeller rejects fluid throughout casing along length of casing mass flow rate increases but increasing area of casing helps in maintaining almost same velocity thus volute casing helps in converting dynamic part of fluid energy to static part it will be interesting struction details of volute casing casing is made on tuvalu curves which are an offset a three-dimensional volute is made from this curves a portion is removed from volute shape in order to accommodate the impeller in it a discharge nozzle is fit at exit portion of the casing most of the time discharge nozzle is diverging in shape for centrifugal pumps of small capacity as we discussed impeller and casing or its main components but for larger centrifugal pumps there will be additional diffuser blades also present in order to reduce velocity further or they aid in dynamic to static energy conversion now we will see how to predict pressure rise blade velocities at inlet and outlet are shown here fluid velocities at inlet and outlet are also marked here you can see fluid velocity increases from Inlet to outlet due to energy addition to fluid the work required for changing inlet velocity condition to outlet is given by this equation we will go through such turbo machinery analysis in a separate video here Q is the flow rate and V theta represents tangential velocity component of flow for a centrifugal pump inlet velocity will be parallel to radius so tangential component at Inlet is zero from here we can find what’s the head rise in meters of fluid outlet blade angle beta can be derived in terms of velocities also flow rate through impeller is given as flow area times radial velocity so head rise in a centrifugal pump can be derived in terms of flow rate using this we can predict what’s the head rise as we change the flow rate for a particular pump geometry and a particular impeller angular velocity most important parameter in this equation is blade outlet angle beta there can be three different pump characteristics depending upon value of this angle first case if beta is less than 90 degree since this term is positive in this case pressure head decreases with increase in flow these kinds of impellers are called backward curved if beta is 90 degree with flow rate there is no change in pressure rise because this term is zero here they are called radial type if beta is more than 90 degree pressure increases with increase in flow rate such blades are called forward curved blades the big question out of these which one is the most suited for industrial use to get answer for this question let’s see how power consumption varies with discharge for each of these cases for backward curved blades as pressure head decreases with discharge power consumption stabilizes with flow in radial blades since pressure does not have any connection with flow rate power consumption increases linearly in forward curved blades sense pressure head increases with flow power consumption increases exponentially making the operation unstable this will lead to burnout of motor so backward curved blades which has got self-stabilizing characteristics in power consumption is the most preferred one in industry to know more practical aspects of centrifugal pumps check the second video thank you

78 thoughts on “Centrifugal Pump Working”

  1. bhanu kiran chaluvadi says:

    Why should we convert dynamic to static energy by using casing ? At all why are we interested in converting dynamic to static energy ?

  2. Learn Engineering says:

    If a direction changing flow is associated with a high velocity, it always leads to energy losses. So it is clever to covert the dynamic part to static to minimize such losses.

  3. Learn Engineering says:

    Check 2nd video on centrifugal pumps to know more about this.

  4. Muneeswaran Ganesan says:

    Thanks for uploading videos. Glad to hear more turbo machinery videos are on the way.

  5. Jimi Bhatt says:

    Good video…thanks

  6. Indra Ida Bagus says:

    Nice vid. But is it good for pump oil at high RPM?

  7. bobby singh says:

    Dear sir
    I need impeller for diesel mono set 1500 rpm. 12 m head at 16 /l.sec discharge can
    you help me please

  8. Learn Engineering says:

    Please watch the second video on Centrifugal pumps. You can get pump performance curves from the manufacturer. After deciding your system curve, you can select proper impeller.

  9. Srinivas T says:

    nice explanation

  10. sujit hensh says:

    good explanation

  11. Learn Engineering says:

    Hi we couldn't find what is a parabolic flow pump. Could you please suggest some reference for this ?

  12. santhana ponnoiy says:


  13. BOJEGOWDA M H says:

    good one

  14. Prasanth P Nair says:

    fantastic one.. thanx for sharing

  15. ben parkin says:

    you have the voice of an angel.

  16. Albert Aromin says:

    can this pump be used for pumping cement plaster? thanks for the reply

  17. Learn Engineering says:

    Usually reciprocating pumps are used for pumping concrete.

  18. Akeem Hart says:

    This may seem like a silly question but at 3:45 what do the variables 'h', 'g' and 'b' represent. I'm guessing 'h' is the change in pressure? but what about the other two?

  19. Learn Engineering says:

    'h' pressure head rise, 'g' is accelaration due to gravity, 'b' is width of impller blades.

  20. Hussain Ali says:

    hello im wondering what is the effect of inlet head on the performance of the pump ?

    and what is the effect of change in kinetic energy of the fluid if the inlet and outlet pipe diameters changes from 25mm to 32mm?

    I need ur asistance asap please

  21. IUnknownxI says:

    great video.

  22. M.Vinay Kumar says:

    not an great explanation   need more

  23. Sirriebo says:

    I would like this video if the Robotic voice was actually understandable, it's a simple subject made difficult by the voice. 

  24. Aj K says:

    Mis-ter Row-bot, ple-eeze tawk nor-mall-ee like you were ay hew-man or dew naught tawk at awl

  25. Hello Kitty Lover Man! says:

    Geeze, what's with the robotic voice?

  26. SUNIL SONI says:

    this video not sufficient for understanding…really

  27. Sukon Somsoda says:

    This looks a lot like a Nautilus sea shell with a few mods. Nature as teacher. 

  28. Porpoise Hork says:

    For a minute there I thought I was watching some odd Anonymous video or something.

  29. Tiffany Edwards says:

    do you people have a problem with the word 'the'

  30. dlwatib says:

    Actors are starving. Please employ one for your narration.

  31. Or Hirshfeld says:

    great stuff

  32. AboutComposites says:

    Perfect! Thanks guys 🙂

  33. mohammed ahmed says:

    waa cashar muhiim ah 

  34. ahmed johani says:

    dear "learn engineering''

    I would like to ask you kindly to provide me with a written material for assembly and disassemble centrifugal pump. In addition, common problems for this kind of pump.

  35. Tiephl Tiep says:


  36. dooshtoomun says:

    Can anyone explain why tangential velocity at inlet = 0? How come he changed the angle of the fluid velocity at the inlet from some angle >90 to a right angle (3:16)?

  37. Aniket Singh says:

    Awesome explanation..thanks a lot 🙂

  38. THAT GUY says:

    since when did the freddy fuck boy become a scientist

  39. Rakshith Gowda B says:


  40. saket chandra mishra says:

    great explanation

  41. عبدالله السليطي says:

    Excellent work but for my opinion if a real person talks it will be batter then a computer.

  42. amit2196 says:

    sir plze upload video on different type of bearing and its application

  43. Dan Alex says:

    sir ,
    How does the volute casing act as a diffuser ? ( and hence change kinetic head to static head ) .
    A diffuser should have only one inlet and outlet right ? ( Please correct me if im wrong )
    But in this case the volute casing has multiple inlet points ( infinite maybe ) at all angular positions and only one outlet .
    Hence isnt the sole purpose of the volute casing to accomodate increase in mass flow rate ( coming in from different angles ) and hence to maintain constant flow velocity at all angular positions ?

  44. pratik kadam says:

    Nice video

  45. Yonatan Shenhav says:

    Why is the mass flow bigger as the flow comes near the outlet? The same flow flows from starting point A to outlet B, how can the mass flow get bigger?

  46. Ajaypandey Pandey says:


  47. Abdullah Mohammed says:

    what do you mean by b2 in last equation?

  48. Boris T. says:

    Why the Radial Blades should be unbalanced?
    I do not understand at all.

  49. kaushal patil says:

    nice video

  50. Nazmul Haque says:

    Thanks a lot

  51. Muhamad Sukron says:


  52. Jon Saw says:

    The voice is annoying.

  53. David Acosta says:

    what is the b2 that appear in the equations?

  54. Stu Kegl says:

    how do you get from the h,Q to the P,Q diagramm? P=h*g*rho*Q ?

  55. Zaw Min says:

    Thank you somuch😁

  56. Takiya Azrin says:

    Don't be lazy. Use your own voice.

  57. Narayanan H says:

    super video

  58. Isaac Addy says:

    Please sir, what will a continues increase in the rpm result in. Pls respond. Urgent.
    I'm a farmer.

  59. a721g5 says:

    Pink sheep's voice

  60. Ruben Contreras says:

    1:26 to 1:30 — "…along the length of casing mass flow rate increases…" Can anyone tell me why does the mass flow rate increase along the length of the casing?

  61. محمد عباس محمد الجمال says:


  62. kem Meechuy says:

    nice vid

  63. ALBANE Fafah says:

    it's so amazing and very interesting, very clear

  64. study from online says:

    pls watch and comment your opinion, if you like pls subscribe

  65. Hari Krishna says:

    Thank you

  66. Evgenii Palamarchuk says:

    Nice video, but you have an incorrect representation of forward curved blades. Outlet angle is ok, but inlet angle should still stay less than 90° (you just made a mirror image, that is not how it should be).
    Also, backward curved impellers are not mostly used because of power curve, but because they are the most effecient ones. Your motor will not burn out unless you are operating out of the designed range

  67. kamesh mahajan says:

    what is the width of impeller b2??

  68. Genta Hatsuiko says:

    tai lo

  69. fightermafia says:

    this is a radial pump, not centrifugal

  70. Hvacr Pro says:

    http://bit.ly/2OcGRbc download pump book

  71. notun projonmer shikkha says:

    Love and respect from Bangladesh

  72. Nayeem Paray says:

    Sir, can we use two centrifugal pumps to lift water at a height of 150ft.

  73. Nayeem Paray says:

    One pump rest at base level and second one rest at a height of 150/2 ft.

  74. Nayeem Paray says:

    It is for agricultural purpose

  75. kaif jawed says:

    Its fucking sick to see so many complaints against such a great explanation.

  76. Mac STRANGE says:

    Very interesting

  77. CEZARR 88 says:

    Это то же са…мое

  78. widiabdul kodirdanu says:

    please make videos in Indonesian or videos equipped with Indonesian subtitles

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