Bioreactor Aeration Rate VVM Converter

Turn a gas flow rate and a working liquid volume into vvm, or a target vvm into the gas flow you need, with the superficial gas velocity when the vessel diameter is known.

Aeration rate calculator

Aeration rate in vvm

The aeration rate of a bioreactor or fermenter is commonly given in vvm: volume of gas per volume of liquid per minute. It is the gas flow rate divided by the working liquid volume, so its unit is 1/min. This converter works in both directions: from a gas flow rate and a working volume to vvm, or from a target vvm and a working volume to the gas flow you need, in L/min, L/h and m³/h.

Enter the vessel inner diameter as well and the converter also gives the cross-section of the vessel and the superficial gas velocity in m/s and cm/s. Flow in L/min, mL/min, L/h or m³/h, volume in L, mL or m³ and diameter in mm, cm or m are converted for you, and each result shows the formula with the converted values.

The gas flow is taken at the conditions of the flow meter. It is not corrected to the pressure or temperature inside the vessel.

How to use the converter

Choose the calculation: find vvm, or find gas flow.
To find vvm, enter the gas flow rate Q and choose its unit. To find the gas flow, enter the aeration rate in vvm.
Enter the working liquid volume V and choose its unit.
Optionally enter the vessel inner diameter D and its unit to get the cross-section A = π × D² ÷ 4 and the superficial gas velocity vs = (Q ÷ 60000) ÷ A, with Q in L/min and D in m.
Press Calculate. The converter changes Q to L/min and V to L, applies vvm = Q ÷ V or Q = vvm × V, and shows the results to 4 significant figures with the formula line.

Worked examples

1. Gas flow into a vessel

50 L/min of gas into 20 L of liquid: vvm = 50 ÷ 20 = 2.500 vvm.

2. Gas flow for a target vvm, with superficial velocity

500 L at 0.5 vvm: Q = 0.5 × 500 = 250.0 L/min = 15.00 m³/h.

With an inner diameter of 0.8 m: A = π × 0.8² ÷ 4 = 0.5027 m², and vs = (250 ÷ 60000) ÷ 0.5027 = 0.008289 m/s (0.8289 cm/s).

3. Scale-up at the same vvm

1 vvm in 2 L needs 2.000 L/min. In 2000 L it needs 2000 L/min = 120.0 m³/h. vvm does not depend on vessel size; the gas flow grows with the volume.

Frequently asked questions

What does vvm mean?

vvm means volume of gas per volume of liquid per minute. It is the gas flow rate divided by the working liquid volume, so its unit is 1/min: 50 L/min of gas into 20 L of liquid is 2.500 vvm.

Does vvm depend on the size of the bioreactor?

No. vvm is independent of the vessel size. At the same vvm the gas flow grows with the volume: 1 vvm needs 2.000 L/min in 2 L and 2000 L/min in 2000 L.

How is the superficial gas velocity calculated?

With the vessel inner diameter D in m, the cross-section is A = π × D² ÷ 4 in m², and the superficial gas velocity is vs = (Q ÷ 60000) ÷ A in m/s, with Q in L/min. Multiply by 100 for cm/s.

Is the gas flow corrected for pressure or temperature?

No. Q is taken at the conditions of the flow meter, not corrected to the vessel pressure or temperature. Enter the flow as your meter reads it.

Disclaimer

This converter gives an estimate only and is not a substitute for a qualified engineer. vvm means volume of gas per volume of liquid per minute (source: IBISBA, MIFE ontology, aeration rate) and is independent of the vessel size. No recommended aeration range is given here. The gas flow is taken at the conditions of the flow meter, not corrected to the vessel pressure or temperature.