Hydraulic Accumulator Formulas

Last Updated on Sunday, 10 April 2011 20:11 Written by Camilo H Rueda Thursday, 31 March 2011 18:09

Hydraulic Formulas - Accumulators

Hydraulic Accumulator Formulas.

Boyle Law, Isothermal change of state of gases.

(The change in the gas volume takes place so slowly that there is sufficient time for the complete exchange of heat between  the N2 and the exterior. At constant temperature)

P₁ x V₁ = P₂ x V₂

Where:

P₁ = Initial Gas Pressure (Psia)
V₁ = Initial Gas Volume (in³)
P₂ = Final Gas Pressure (Psia)
V₂ = Final Gas Pressure (in³)

Psia = Psig + 14.7 psi

Adiabatic change of state of gases.

(The change in the gas volume takes place so rapidly that the temperature of the N2 also changes)

P₁ x V₁ⁿ = P₂ x V₂ⁿ

Where:

n = Molar specific heat ratio for N₂ (Nitrogen) = 1.4

Finding the size of the accumulator needed:

Adiabatic change ( fast charge & discharge)

P₁ = Gas Pre-charge

ΔV = V₁ - V₂ = Available Volume for Discharge

P₂ = Maximum System pressure

n = 1.4 for N₂

V₁ = [P₂/P₁]^1/1.4 x V₂