Flow Mass Conversion Hub

Understanding Mass Flow Rate & Conservation of Mass

Mass flow rate (symbolized as $\dot{m}$) represents the mass of a substance passing per unit time through a specific boundary. Unlike volumetric flow rate, which changes when fluid expands or contracts with temperature and pressure, mass flow rate remains strictly conserved across steady-state thermodynamic processes.

Continuity Principle & Coriolis Measurement

Mass flow is related to volumetric flow and fluid density via:

$$\dot{m} = \rho \cdot Q = \rho \cdot A \cdot \bar{v}$$

In compressible flow and aerospace propulsion, mass flow rate dictates rocket thrust according to $F_{thrust} = \dot{m} v_e + (P_e - P_a) A_e$. Coriolis mass flow meters measure $\dot{m}$ directly by detecting phase shifts induced by the Coriolis effect on vibrating flow tubes, completely independent of fluid viscosity or density variations.

Standard Units & Exact Multipliers

• SI Metric: Kilogram per second ($\text{kg}/\text{s}$), kilogram per hour ($\text{kg}/\text{h}$), and metric ton per day ($\text{t}/\text{day}$). $1\text{ kg}/\text{s} = 3,600\text{ kg}/\text{h} = 86.4\text{ t}/\text{day}$.
• Imperial Engineering: Pound per hour ($\text{lb}/\text{hr}$) and pound per second ($\text{lb}/\text{s}$). $1\text{ kg}/\text{s} \approx 2.204623\text{ lb}/\text{s} \approx 7,936.64\text{ lb}/\text{hr}$.
• Laboratory Precision: Gram per second ($\text{g}/\text{s}$) and milligram per minute ($\text{mg}/\text{min}$).

Engineering Applications

Fundamental for boiler feedwater dosing, aircraft turbofan fuel flow telemetry, continuous chemical batch blending, and semiconductor vapor deposition mass flow controllers (MFCs).