Toolbox Equations Flowserve

8/17/2019 Toolbox Equations Flowserve

1/9

1

Pump Formulas — Imperial and SI Units

Pressure to Head

Imperial Units SI Units

H = head, ftP = pressure, psiSG = specific gravity

H = head, mP = pressure, barSG = specific gravity

Mass Flow to Volumetric Flow

Imperial Units SI Units

Q = flow, gpmṁ = mass flow, lbm/hSG = specific gravityρ = fluid density, lbm/ft

3

Q = flow, m /hṁ

= mass flow, kg/hρ = fluid density, kg/m

3

Net Positive Suction HeadIn terms of head Imperial Units SI Units

NPSH = net positive suction head at reference point(usually center line of the impeller), ftHa = absolute pressure of the suction vessel, ftHvpa = fluid vapor pressure at pumping temperature, ftHst = static head to suction reference point (usually centerline of the impeller), ftHfs = suction line losses, ft

NPSH = net positive suction head at reference point(usually center line of the impeller), mHa = absolute pressure of the suction vessel, mHvpa = fluid vapor pressure at pumping temperature, mHst = static head to suction reference line (usually centerpoint of the impeller), mHfs = suction line losses, m


2/9

2

In terms of pressure and head Imperial Units SI Units

NPSH = net positive suction head at reference point(usually center line of the impeller), ftPa = absolute pressure of the suction vessel, psiaPvpa = fluid vapor pressure at pumping temperature, psiaHst = static head at reference point (usually center line of

the impeller), ftHfs = suction line losses, ftSG = specific gravity

NPSH = net positive suction head at reference point(usually center line of the impeller), mPa = absolute pressure of the suction vessel, kPaPvpa = fluid vapor pressure at pumping temperature, kPaabsolute

Hst = static head to suction reference line (usually centerpoint of the impeller), mHfs = suction line losses, mρ = fluid density, kg/m

3

g = gravitational constant, 9.81 m/s2

Pump HeadImperial Units SI Units

H = pump head, ftHf = friction loss, ftPS = suction pressure, psiaPd = discharge pressure, psiaSG = specific gravityVs = suction velocity, ft/sVd = discharge velocity, ft/sZs = suction height from reference, ftZd = discharge head from reference, ftg = gravitational constant, 32.2 ft/s

2

H = pump head, mHf = friction loss, mPS = suction pressure, barPd = discharge pressure, barSG = specific gravityVs = suction velocity, m/sVd = discharge velocity, m/sZs = suction height from reference, mZd = Discharge head from reference, mg = gravitational constant, 9.81 m/s

2


3/9

3

Pump PowerImperial Units SI Units

P = power, horse powerH = head, ftQ = flow, gpmSG = specific gravity

= pump efficiency, decimal

P = power, kWH = head, mQ = flow, m

3 /hr

SG = specific gravity

= pump efficiency, decimal

Pump TorqueImperial Units SI Units

τ = torque, ft-lbfP = pump power, hpN = pump speed, rpm

τ = torque, N-mP = pump power, kWN = pump speed, rpm

Temperature RiseImperial Units SI Units

ΔT = temperature rise, °FH = total head, ftη = pump efficiency, decimal U = fluid specific heat, BTU/(lbm-°F)

ΔT = temperature rise, °C or °K H = total head, mη = pump efficiency, decimal U = fluid specific heat, kJ/(kg-°K) or kJ/(kg-°C)


4/9

4

Fluid VelocityImperial Units SI Units

V = velocity, ft/sQ = flow, gpmd = pipe inside diameter, in

V = velocity, m/sQ = flow, m

3 /h

d = pipe inside diameter, mm

Velocity HeadImperial Units SI Units

Hv = velocity head, ft of liquidV = fluid velocity, ft/sg = gravitational constant, 32.2 ft/s

2

Q = flow, gpmd = pipe inside diameter, in

Hv = velocity head, mV = fluid velocity, m/sg = gravitational constant, 9.81 m/s

2

Q = flow, m3 /h

d = pipe inside diameter, mm

Specific Speed at BEPImperial Units SI Units

Ns = specific speedN = pump speed, rpmQ = flow, gpm

H = head, ftValues are taken at best efficiency point (BEP)Pump flow is taken at the largest impeller diameterFor double suction impellers pump flow is divided by two

Ns = specific speedN = pump speed, rpmQ = flow, m

3 /h

H = head, mValues are taken at best efficiency point (BEP)Pump flow is taken at the largest impeller diameterFor double suction impellers pump flow is divided by two


5/9

5

Suction Specific Speed at BEPImperial Units SI Units

Ns = specific speedN = pump speed, rpmQ = flow, gpm

NPSH = net positive suction head, ftValues are taken at best efficiency point (BEP)Pump flow is taken at the largest impeller diameterFor double suction impellers pump flow is divided by two

Ns = specific speedN = pump speed, rpmQ = flow, m

3 /h

NPSH = net positive suction head, mValues are taken at best efficiency point (BEP)Pump flow is taken at the largest impeller diameterFor double suction impellers pump flow is divided by two


6/9

6

Other Pump Formulas

Affinity LawsChanges in Diameter Changes in Speed

D = diameter, in or mmQ = flow, gpm or m

3 /h

H = head, ft or mP = power, hp or kW

Q = flow, gpm or m /hH = head, ft or mP = power, hp or kWN = speed, rpm

Bernoulli’s Equation

g = gravitational constantL = energy lossesPS = suction pressurePd = discharge pressureVs = suction velocityVd = discharge velocityW = work by the pumpZs = suction height from referenceZd = discharge head from referenceρ = fluid density

γ = fluid specific weight = g*ρ


7/9

7

Tables

Conversion FactorsImperial Conversions From To Multiply By

barrel (oil) – bbl gallon – US gal 42barrel (oil) – bbl cubic meter – m3 0.159 0British thermal unit – Btu Joule – J 1 055

British thermal unit per hour – Btu/h Watt – W 0.293 1cubic feet – ft3 cubic meter – m3 0.028 32cubic feet per minute – ft /min or cfm cubic meters per hour – m h 1.699feet – ft meter – m 0.304 8foot pounds force – ft-lbf Joule – J 1.356gallon (US) – US gal cubic meter – m3 0.003 785gallon (US) – US gal liter – l 3.785gallon (US) – US gal gallon (Imperial) – Imp gal 0.832 7gallon (US) per minute – gpm cubic meter per hour – m3 /h 0.227 1gallon (US) per minute – gpm barrel (oil) per day – b/d 34.28horsepower – hp kilowatt – kW 0.745 7horsepower hour – hp-h kilojoule – kJ 2 684horsepower hour – hp-h British thermal unit per hour – Btu 2 545inch – in millimeter – mm 25.4inch of mercury at 0°F – inHg kilopascal – kPa 3.386inch of water at 68°F – inH2O kilopascal – kPa 0.248 7mile kilometer – km 1.609pound force – lbf Newton – N 4.448pound mass – lbm kilogram – kg 0.453 6pound force per square inch – psi kilopascal – kPa 6.895pound force per square inch – psi bar 0.068 95ton (long) ton (short) 1.12ton (short) kilogram – kg 907.2

yard – yd meter – m 0.914 4Note

1. Conversions less than four significant digits are exact.


8/9

8

SI Conversions From To Multiply Bybar kilopascal – kPa 100bar pounds force per square inch – psi 14.50cubic meter – m3 gallons – US gal 264.2cubic meter – m3 cubic feet – ft3 35.31cubic meter per hour – m /hr gallons per minute – gpm 4.403cubic meter per hour – m3 /hr barrel per day – b/d 337.3kilograms – kg pounds mass – lbm 2.205

kilogram per square centimeter – kg/cm2

Bar 0.980 7kilogram per square centimeter – kg/cm2 pounds force per square inch – psi 14.22kilometer – km mile 0.621 4kilopascal – kPa pounds force per square inch – psi 0.145 0kilowatt – kW horsepower – hp 1.341kilowatt hour – kW-h British thermal units per hour – Btu 3.413kilowatt hours – kW-h Kilojoule – kJ 3 600meter – m feet – ft 3.281Newton – N pound force – lbf 0.224 8

SI PrefixesPower of Ten Name Symbol1012 tera T10 giga G106 mega M103 kilo k10 deca da10-1 deci d10-2 centi c10-3 milli m10-6 micro μ 10- nano n

10-12

pico p


9/9

9

Symbols and NomenclatureSymbol Definition Imperial Units SI UnitsA Area ft2 m2 D, d Diameter inches mmg Gravitational constant 32.2 ft/s2 9.81 m/s2 H Head ft mh Time hour hourṁ Mass flow rate lbm/h kg/hN Speed rpm rpmNs Specific speed Dimensionless DimensionlessNss Suction specific speed Dimensionless DimensionlessP Power horsepower kWP Pressure psi kPa or barQ Flow gpm m /hs Time seconds secondsU Specific heat btu/lbm-°F kJ/kg-°CV Velocity ft/s m/sW Work ft mZ Elevation ft mNPSH Net positive suction head ft mSG Specific gravity Dimensionless Dimensionless

η Efficiency Dimensionless Dimensionlessρ Density lbm/ft3 Kg/m3 τ Torque ft-lbf N-m

ΔT Temperature change °F °Cγ Specific weight lbf/ft3 kN/m3

Toolbox Equations Flowserve

Documents

Transcript of Toolbox Equations Flowserve