Turbo machinery: is a device that exchanges energy with a fluid using continuously flowing fluid and rotating blades. Examples are : Wind turbines,

Transcription

1 . Introduction

2 urbo machinery: i a device that exchange energy with a fluid uing continuouly flowing fluid and rotating ble. Example are : Wind turbine, Water turbine, Aircraft engine. 2

3 laification of urbomachine urbomachine can be claified in two main group; A. ower Machine (urbine): extract energy from flow medium and tranfer it to haft of the machine. According to the available kind of energy power machine can be further claified a:. Water turbine : convert eure energy 2. Wind turbine: convert kinetic energy of the air 3. Heat urbine: onvert heat energy of the ga or team a. team turbine: b. Ga turbine 3

4 Machine for Extracting Work (ower) from a Fluid 4

5 B. Working Machine (ump): deliver energy from the haft of the machine to the flow medium. According to the kind of flow medium and eure generated working machine are further claified into:. ump (Liquid Medium) 2. omeor (Ga Medium) a. Fan Low eure rie b. Blower medium reure rie c. urbo omeor high eure rie 5

6 Machine for oing Work on a Fluid 6

7 laification of urbomachine bae on the way in which the flow pae through h the rotor: I. Axial flow Machine: the direction of the flow in the meridian ection iparallel l to theaxiof the rotor Flow path ~ parallel to axi of rotation II. Rial flow Machine: the direction of the flow in the meridian ection i perpendicular to the rotor: Flow path ~ perpendicular to axi of rotation III. Mixed flow Machine: he direction of the flow in the meridian ection ha a component parallel a well a perpendicular to the axi of the rotor. 7

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11 urbomachine have alway a vaned rotor and often tationary vane (guide vane). he guide vane are motly located at the eure end of the machine. reure end/flange: i the part at which the energy poeed by the fluid i a maximum: In working machine, the exit end i the eure end In power machine the inlet end i the eure end uction end/flange: i the part at which the energy poeed b the fluid i a minimum. i In working machine, the inlet end i the eure end In power machine the exit end i the eure end

12 he pecific Work [ ] 2 he difference of the ueful pecific energy content of the flow medium between the two end of themachine idefined a pecific work done between inlet and outlet of the machine m 2 Regarding the energy tranfer in a turbomachinery i to be noted that: a. an increae/decreae of the ueful energy content of the flow medium in the cae of working/power machine, b. andalwayand alway increae of the non utilizable energy content of the flow medium. 2

13 Energy aborbed by the flow medium due to flow loe. hi energy i non-utilizable. otal energy tranferred from impeller to the flow medium Ueful energy rie of the flow medium Flow energy tranferred into torque otal energy available (ueful) ump urbine 3

14 From Bernoulli Equation: otal Energy reure + Energy Velocity Energy + geodetic Energy hu pecific energy can be given by the formula: 2 2 m vdp + + g ( Z Z ) vel geo 2 Where: vdp geo vel g ( Z Z ) Z Z pecific eure work kinetic energy pecific geodetic dti energy 4

15 pecific energy content of the flow medium between and end of the machine can be exeed interm of He H. 2 m 2 m g 2 H[ m ] Note that the value of H will change if the machine work in another field of gravity contrary to the value of which doe not change with g. i alway meaured between the uction and eure end of the machine. In the cae of water turbine the tail race urface i conidered a the uction end. 5

16 Often the equation for can be implified: In the cae of Wind turbine where only velocity energy i available, it i: vel 2 Inthe cae of team turbine, the velocity and geodetic energy can be neglected a both are very mall compared with the eure energy, Inthe cae of pump with equal diameter of uction and eure flange, the velocity energy i zero. 2 2 vdp + geo 6

17 etermination of the reure Energy he eure energy reeent the needed work to change the tatic eure of the flow medium from to by a oce without loe. In cae of an incomeible medium the eure energy i: dp vdp ρ ρ In cae of a comeible medium the denity i changing from to. ha to be determined by integration: vdp dp ρ 7

18 onider ientropic oce AB he coure AB i given by the equation:. v cont. where k V he value of the cont can be determined from the known inlet condition: comeion :. v exp anion :. v v v. v.. 8

19 omeion (umping Machine) p ( p g ) Integration: dp v vdp R k k v k k V R k k nd R t con ga a tan N i t i f th id l F : kg kcal kg Nm kg Nm R Air For : ρ give thi oce ientropic for theory ga From ideal,, :, kg kcal kg Nm kg kg V ( ) 9

20 Expanion (turbine) Expanion (turbine) Integration: dp v vdp R k k v k k ( ) gae perfect For imilarly ( ) team For i i gae perfect For 20

21 in, iagram a. omeion p c For ientropic oce: ' ' For ientropic oce: ( ) d t or hence Δ, ' ' For iabatic oce: ( ) p t c t or Δ Δ 0 d c di A vdp di vdp di or vdp di dq ' d c 2

22 hu, i obtained if the integration i done from to along a line of cont. p for intance along the eure : Δt AB B i reeented by the area 22

23 B. Expanion where Δt c p Δt c p ( ' ) i reeented by the area AB B 23

24 in i, iagram ' a. omeion: vdp di i ' i Δ i i i and i reeented tdby the ditance AB. 24

25 in i, iagram b. expanion: vdp di i i ' Δ i i i ' and i reeented tdby the ditance AB. 25

26 he power he amount of the power change of the continuou flow which pae the machine i: N eff M ρv Nm or [ W ] oupling power effective power for ideal machine that operate without ih any loe An actuallymachine involve loe. hu the coupling power of the machine i: ρv for pump m N η ρv η ρv η for turbine 26