Hydrauliska Strömningsmaskiner

Innehåll
1.INLEDNING............................................................................................................................ 1
1.1 Strömningsmaskiners indelning ....................................................................................... 1
1.2 Vanliga utförandeformer .................................................................................................. 4
1.2.1 Pumpar....................................................................................................................... 4
1.2.2 Fläktar........................................................................................................................ 5
1.2.3 Vattenturbiner............................................................................................................5
2. GRUNDLÄGGANDE TEORI ............................................................................................... 7
2.1 Hastighetstrianglar............................................................................................................ 7
2.2 Kontinuitetsekvationen..................................................................................................... 8
2.3 Impulslagen....................................................................................................................... 9
2.4 Impulsmomentekvationen............................................................................................... 10
2.5 Eulers ekvation ............................................................................................................... 12
2.6 Energiekvationen ............................................................................................................ 13
2.7 Pump- och fläktdiagram ................................................................................................. 14
2.7.1 Pumpkurvans utseende ............................................................................................ 15
2.7.2 Pumpdiagram........................................................................................................... 16
2.7.3 Fläktdiagram............................................................................................................ 17
2.8 Likformighets- och affinitetslagarna .............................................................................. 18
2.8.1 Likformighetslagarna............................................................................................... 18
2.8.2 Affinitetslagarna ...................................................................................................... 20
2.9 Specifikt varvtal.............................................................................................................. 21
2.10 Dimensionslösa tal........................................................................................................ 23
2.11 Systemkurva–driftpunkt ............................................................................................... 25
3. PUMPAR.............................................................................................................................. 26
3.1 Olika slag av pumpar...................................................................................................... 26
3.1.1 Pumpar med fri strömning....................................................................................... 26
3.1.2 Uppdelning av uppfordringshöjden ......................................................................... 27
3.1.3 Uppdelning av volymströmmen .............................................................................. 27
3.2 Uppfordringshöjd............................................................................................................ 28
3.2.1 Pumpens uppfordringshöjd...................................................................................... 28
3.2.2 Systemets uppfordringshöjd .................................................................................... 28
3.2.3 Sughöjd.................................................................................................................... 29
3.2.4 Pumpeffekt, effektbehov och verkningsgrad........................................................... 29
3.2.5 Pumpkurva och pumpdiagram................................................................................. 30
3.2.6 Parallelldrift av rotodynamiska pumpar .................................................................. 31
3.2.7 Seriedrift av rotodynamiska pumpar........................................................................ 33
3.3 Styrning av volymströmmen........................................................................................... 33
3.3.1 Strypning.................................................................................................................. 34
3.3.2 Varvtalsändring........................................................................................................ 34
3.3.3 Skovel- och ledskenereglering................................................................................. 36
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