Stability Analysis of a Direct-Operated Seawater Hydraulic Relief Valve under Deep Sea

Table 1

Main structure parameters of the relief valve.

Physical quantity	Sign	Value selection
Valve port flow coefficient		0.8
Seawater dynamic viscosity (Pa⋅s)		0.001
Elasticity modulus of seawater bulk (MPa)		1780
Diameter of front section of damping bar (mm)		10
Initial fitting clearance of front section of damping bar (mm)		0.02
Matched length of front section of damping bar (mm)		6.5
Initial length of damping cavity (mm)		3
Pressure value of working point (MPa)		14
Precompressed spring length (mm)		10.28
Pipeline volume from pump outlet to valve inlet (L)		2
Valve port speed coefficient		0.8
Seawater density (kg⋅m^−3)		1025
Diameter of valve port (mm)		6
Contact surface diameter of back section of damping bar (mm)		6
Initial fitting clearance of back section of damping bar (mm)		0.02
Matched length of back section of damping bar (mm)		8
Equivalent mass of moving parts (g)		40
Stiffness coefficient of spring (N⋅mm^−1)		34.59
Working point spring compression variation (mm)		0.20
Pump outlet flow (L⋅min^−1)		30