How to Calculate Mass Flow Rate from Volume Flow Rate

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Mass Flow Rate Calculator

m³/s Liters per minute (LPM) Gallons per minute (GPM) Cubic Feet per minute (CFM)
kg/m³ g/L lb/gal

Understanding and Calculating Mass Flow Rate

Mass flow rate is a crucial concept in fluid dynamics, engineering, and many scientific fields. It quantifies the amount of mass of a substance that passes through a given surface per unit of time. This is distinct from volume flow rate, which measures the volume passing per unit time. While related, mass flow rate accounts for the density of the substance, making it a more fundamental measure in many applications, such as chemical reactions, combustion processes, and fluid transfer systems.

The Relationship Between Volume Flow Rate and Mass Flow Rate

The fundamental relationship between mass flow rate and volume flow rate is:

Mass Flow Rate = Volume Flow Rate × Density

This formula highlights that to determine the mass flow rate, you need to know both how much volume is moving and how much mass is contained within that volume (its density).

Units of Measurement

It's essential to use consistent units when performing this calculation. The common units for each variable are:

  • Volume Flow Rate: cubic meters per second (m³/s), liters per minute (LPM), gallons per minute (GPM), cubic feet per minute (CFM).
  • Density: kilograms per cubic meter (kg/m³), grams per liter (g/L), pounds per gallon (lb/gal).
  • Mass Flow Rate: kilograms per second (kg/s), grams per second (g/s), pounds per minute (lb/min).

How to Use the Calculator

This calculator simplifies the process of converting volume flow rate to mass flow rate.

  1. Enter the Volume Flow Rate: Input the measured or known volume flow rate of the substance.
  2. Select Volume Flow Rate Units: Choose the appropriate units for your volume flow rate from the dropdown menu.
  3. Enter the Density: Input the density of the substance.
  4. Select Density Units: Choose the appropriate units for your density from the dropdown menu.
  5. Click "Calculate Mass Flow Rate": The calculator will then output the mass flow rate in standard units (kg/s).

Example Calculation

Let's say you have water flowing at a rate of 50 liters per minute (LPM). The density of water at room temperature is approximately 1 kilogram per liter (kg/L).

Using the calculator:

  • Volume Flow Rate: 50
  • Volume Unit: Liters per minute (LPM)
  • Density: 1
  • Density Unit: kg/L

The calculator will output a mass flow rate of approximately 0.833 kg/s. This is because 50 LPM is equivalent to 0.000833 m³/s. When multiplied by the density of 1000 kg/m³ (equivalent to 1 kg/L), the result is 0.833 kg/s.

Understanding and accurately calculating mass flow rate is vital for numerous industrial and scientific processes. This calculator provides a quick and reliable way to perform this conversion.

function calculateMassFlowRate() { var volumeFlowRate = parseFloat(document.getElementById("volumeFlowRate").value); var density = parseFloat(document.getElementById("density").value); var volumeUnit = document.getElementById("volumeUnit").value; var densityUnit = document.getElementById("densityUnit").value; var resultDiv = document.getElementById("result"); if (isNaN(volumeFlowRate) || isNaN(density)) { resultDiv.innerHTML = "Please enter valid numbers for volume flow rate and density."; return; } var volumeFlowRate_m3_per_sec = 0; var density_kg_per_m3 = 0; // Convert volume flow rate to m³/s if (volumeUnit === "m3_per_sec") { volumeFlowRate_m3_per_sec = volumeFlowRate; } else if (volumeUnit === "lpm") { volumeFlowRate_m3_per_sec = volumeFlowRate / 60000; // 1 L = 0.001 m³, 1 min = 60 s } else if (volumeUnit === "gpm") { volumeFlowRate_m3_per_sec = volumeFlowRate * 0.0000630902; // 1 US Gallon = 0.00378541 m³, 1 min = 60 s } else if (volumeUnit === "cfm") { volumeFlowRate_m3_per_sec = volumeFlowRate * 0.000471947; // 1 cubic foot = 0.0283168 m³, 1 min = 60 s } // Convert density to kg/m³ if (densityUnit === "kg_per_m3") { density_kg_per_m3 = density; } else if (densityUnit === "g_per_l") { density_kg_per_m3 = density / 1000; // 1 g/L = 1 kg/m³ } else if (densityUnit === "lb_per_gal") { // 1 lb = 0.453592 kg // 1 US gallon = 0.00378541 m³ density_kg_per_m3 = density * 0.453592 / 0.00378541; } var massFlowRate_kg_per_sec = volumeFlowRate_m3_per_sec * density_kg_per_m3; resultDiv.innerHTML = "Mass Flow Rate: " + massFlowRate_kg_per_sec.toFixed(4) + " kg/s"; }

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