免费质量流量计算器
根据密度和体积流量计算质量流量。
质量流量
15.708 kg/s
Mass Flow Rate vs Fluid Density (rho)
公式
## Mass Flow Rate Mass flow rate is the mass of fluid passing through a cross-section per unit time. It is a fundamental quantity in fluid mechanics, thermodynamics, and process engineering. ### Formula **m_dot = rho × V × A** where rho is the fluid density, V is the average velocity, and A is the cross-sectional area. For a circular pipe, A = pi × D² / 4. Mass flow is conserved through a system (continuity equation).
计算示例
Water (1000 kg/m³) flowing at 2 m/s through a 100 mm pipe.
- 01D = 100 mm = 0.1 m
- 02A = pi × 0.1² / 4 = 0.007854 m²
- 03m_dot = 1000 × 2 × 0.007854 = 15.708 kg/s
- 04Volume flow = 2 × 0.007854 × 1000 = 15.708 L/s
常见问题
Why use mass flow instead of volumetric flow?
Mass flow is independent of temperature and pressure changes. Volumetric flow varies with density (especially for gases). For energy and mass balance calculations, mass flow rate is preferred.
What is a typical pipe velocity for water?
For water in process piping: 1-3 m/s for pump suction, 2-4 m/s for pump discharge, 0.5-1 m/s for gravity flow. Too high a velocity causes erosion and excessive pressure drop.
How does the continuity equation work?
At steady state, mass flow in = mass flow out for any control volume. If a pipe changes diameter, rho1 × V1 × A1 = rho2 × V2 × A2. For incompressible flow, V1 × A1 = V2 × A2.
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