[LDi] Liquid Dynamics International Liquid Dynamics International Inc. Click here to: Contact Liquid Dynamics Liquid Dynamics offers pulsation, vibration, and shock analysis, diagnostics, and software models. Fluid Flow Control Animations
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MODELING
Pub 4 Main Menu


ShockView schematic

ShockView plots A, B, C

Input data for shock modeling

PulseView models relations

7 ocillographic plots

Necess. program input data

Equations& sources

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Predict valve, membrane, & liquid mass motion, responses to flow from reciprocating pump action, to generate the pressure pulsation.
Ex: Initial choice, outline of equations, for compiling a fortran "dt" iterativeLDi shock analysis software display for motions & resultant pressure pulsation.

Note, in this primitive skeletal outline example of LDi method, position numbers: D, G, L, P, & V, 00, 01, 02, 03, 04, etc. are aspg. 29.

Symbols - Img 1Symbols - Img 2Symbols - Img 3Symbols - Img 4

Assumption in this example are: That there is no vortex or other instability at system inlet, and that the system load, is not applied by a "spill back loop" or a "controller" that "modulates" open and closed.

1.
Constant
Suction Source, Load
Ref.
2.
Number 2
Suction Manifold Inlet Flow
A
3.
Number 3
Suction Manifold Outlet Flow
A
4.
Number 4
Suction Manifold Pressure Balance
B
5.
Number 5
Suction Check Inlet Mass Flow
A
6.
Number 6
Suction Check Pocket Flow Balance
B
7.
Number 7
Suction Check Motion
C
8.
Number 8
Piston Position
A
9.
Number 9
V11 Flow Balance
B
10.
Number 10
V11 Volume Change
 
11.
Constant
Load
 
12.
Number 12
Discharge Check Inlet Mass Flow
A
13.
Number 13
Discharge Check Motion
C
14.
Number 14
Discharge Check Pocket Flow Balance
B
15.
Number 15
Discharge Check Outlet Mass Flow
A
16.
Number 16
Discharge Manifold Pressure Balance
B
17.
Number 17
Discharge Manifold Outlet Mass Flow
A

References: A. Pump Handbook, 2nd Ed. Karassik eq 38., p.3.8. B. Mechanics of Fluids, 6th Ed. Massey eq 13.14 & 13.16 C. Handbook of Noise & Vibration, 6th Ed. Barber, M.I.T. 1960 Library of Congress Cat Card Nbr 59-6759 E&OEE

Whilst LDi PulseView software also displays "acoustics", it is primarily a mass, motion, & pressure model - not an attempt to determine them from "acoustic" frequencies and amplitudes.

 

Y & Z – Valve position, m Nfr – Coulomb friction force, N F – Area meters squared m2 Cfr – Viscous friction coefficient, N sec/m p – Density, kg/m3 P – Pressure, Pa G – Mass flow, Kg/sec Cspr – Spring rating, N/m w – Angular velocity, 1/radius R – Crankshaft radius, m l – L/F – Fluid column inertia, 1/m D – Diameter, m In these descriptions: N – Newtons, m – meters, Pa - Pascals X – Piston position, m T – Time, sec m – Mass, Kg L – Length, m E – Bulk modulus of liquid, Pa
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Liquid Dynamics International provides pipeline and pump user problem analysis, diagnostics, prediction by software, pulsation analysis, piping system analysis, and piping system simulation. For water hammer and shock solutions pulsation dampening and shock alleviating devices can be obtained from our associate websites.

PulseGuard Inc., and Ltd. for further information about pulsation dampeners / pulsation dampers.
PulseGuard. USA: Pulsation Dampeners | Pulsation-Dampeners.com: Pulsation Dampeners
PulseGuard Limited: Pulsation Dampers | PulseGuard für Deutschland: Pulsationsdämpfer

Large pressure vessels, jumbo bladders, float separator / big bellows type pipeline surge attenuators and
expansion / contraction volume compensators, surge alleviators, and shock alleviators.

Shock-Guard. USA: Surge Alleviators | Water-Hammer.com: Water Hammer
ShockGuard.co.uk: Shock Alleviators | Suction-Stabilizers: Suction Stabilizers

Information about energy saving in pumping systems, standby emergency power, safety shutdown systems,
hydraulic accumulators, and hydropneumatic accumulators.

Accumulators-Hyd: Hydraulic Accumulators
Accumulators.co.uk: Hydropneumatic Accumulators | HydroTrole: Hydraulic and Control Engineering

Protection against excess flow. Protect against toxic spills when pipes burst, guard against gushers and fluid
loss when hoses split. Flow-Guard against excess flow floods with flow fuses and breather bags.

FlowGuard: Flow-Guard - Flow Fuses and Breather Bags




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