Fluid Property Calculator
Analyze physical characteristics including density, specific gravity, and viscosity.
Analysis Results
Understanding Fluid Properties in Engineering
Fluid properties are fundamental characteristics that define how a liquid or gas behaves under various physical conditions. Whether you are designing a hydraulic system, a chemical reactor, or an HVAC network, accurately calculating these values is essential for predicting flow rates, pressure drops, and heat transfer efficiency.
Density and Specific Gravity
Density (ρ) is defined as the mass of a substance per unit volume. In the International System of Units (SI), it is measured in kilograms per cubic meter (kg/m³). It is a direct indicator of how "heavy" a fluid is for its size.
Specific Gravity (SG) is a dimensionless ratio comparing the density of a fluid to the density of a reference substance (usually pure water at 4°C, which is 1,000 kg/m³). If a fluid has an SG of 0.8, it is 80% as dense as water and will likely float.
Viscosity: Dynamic vs. Kinematic
Viscosity measures a fluid's resistance to deformation or flow. Dynamic Viscosity (μ), also known as absolute viscosity, relates shear stress to the rate of deformation. Kinematic Viscosity (ν) is the ratio of dynamic viscosity to density, representing the fluid's inherent resistance to flow under the influence of gravity.
Common Fluid Properties Reference
| Fluid (at 20°C) | Density (kg/m³) | Dynamic Viscosity (Pa·s) |
|---|---|---|
| Water | 998 | 0.001002 |
| Engine Oil (SAE 30) | 890 | 0.29 |
| Glycerin | 1,260 | 1.49 |
| Mercury | 13,546 | 0.001526 |
Calculation Formulas Used
This calculator utilizes the following fundamental physics equations:
- Density: ρ = m / V
- Specific Gravity: SG = ρfluid / ρwater(1000)
- Specific Weight: γ = ρ × g
- Kinematic Viscosity: ν = μ / ρ
Practical Example
Suppose you have a sample of hydraulic oil with a mass of 850 kg occupying a volume of 1 cubic meter. If the dynamic viscosity is 0.02 Pa·s, the calculation would be:
- Density: 850 / 1 = 850 kg/m³
- Specific Gravity: 850 / 1000 = 0.85
- Specific Weight: 850 × 9.81 = 8,338.5 N/m³
- Kinematic Viscosity: 0.02 / 850 = 0.0000235 m²/s