| Commonly used physical quantities, symbols and units in hydraulics | ||
| physical quantity | notation | common unit |
| Area | \(A\) | \(mm^2\) |
| Shrinkage factor | \(C_c\) | |
| Flow rate coefficient | \(C_d\) | |
| Flow rate coefficient | \(C_v\) | |
| Diameter | \(D、d\) | \(mm\) |
| Eccentricity | \(e\) | \(mm\) |
| Force | \(F\) | \(kN\) |
| Frequency | \(f\) | \(H_z\) |
| Acceleration | \(g\) | \(m/s^2\) |
| Height | \(h\) | \(cm\) |
| Modulus of elasticity by volume | \(E\) | \(Pa\) |
| Length | \(L、l\) | \(mm\) |
| Gear modulus | \(m\) | \(mm\) |
| Mass | \(m\) | \(kg\) |
| Index | \(n\) | |
| Rotational frequency (rpm) | \(n\) | \(l/s\) |
| Power | \(P\) | \(kW\) |
| Pressure, differential pressure | \(p、\Delta p\) | \(MPa\) |
| Input pressure | \(P_i\) | \(MPa\) |
| Rated pressure | \(P_n\) | \(MPa\) |
| Output pressure | \(P_o\) | \(MPa\) |
| Flow rate | \(q\) | \(L/min\) |
| Volume flow rate | \(q_v\) | \(L/min\) |
| Flow rate at zero pressure | \(q_{v0}\) | \(L/min\) |
| Mass flow rate | \(q_m\) | \(g/min\) |
| Radius | \(R、r\) | \(mm\) |
| Torque | \(T\) | \(N\cdot m\) |
| Time | \(t\) | \(s\) |
| Displacement, volume, volumetric | \(V\) | \(mL、L、m^3\) |
| Instantaneous displacement, velocity, flow rate | \(v\) | \(mL/r、mm/s、m/s\) |
| Number of Actions | \(x\) | |
| Number of plunger rows | \(y\) | |
| Number of teeth (or blades or plungers) | \(z\) | |
| Angle of pinch, coefficient of body expansion | \(\alpha \) | \((^\circ )、1/^\circ C\) |
| Oscillation angle | \(\beta \) | \((^\circ )\) |
| Gap | \(\delta \) | \(mm\) |
| Efficiency | \(\eta \) | \(\%\) |
| Hydromechanical efficiency | \(\eta _{hm}\) | \(\%\) |
| Total efficiency | \(\eta _0\) | \(\%\) |
| Volume efficiency | \(\eta _v\) | \(\%\) |
| Coefficient of resistance along the course | \(\lambda \) | |
| Temperature | \(\theta \) | \(^\circ C\) |
| Dynamic viscosity | \(\mu \) | \(Pa\cdot s\) |
| Pneumatic isentropic index | \(\kappa \) | |
| Kinematic viscosity | \(v\) | \(mm^2/s\) |
| Local drag coefficient | \(\xi \) | |
| Density | \(\rho \) | \(kg/m^3\) |
| Surface Tension | \(\sigma \) | \(N/m\) |
Contact Zhuo Yi Control Technology for the latest advancements in hydraulics production technology! For more information or any inquiries, you can reach us by email or WhatsApp. We look forward to assisting you!
