I need convert ar flow unit : Nl/min to m³/hour. What does Nl/min means ? Is it a usual unit to flow meter ?
The "N" means "normal." Regardless of the actual temperature and pressure of the measurement, the flow has been calculated as though the conditions were 0 °C, 101.325 kPa. Conditions have a major effect on the volume of a gas, and some effect on the volume of a liquid, mostly due to temperature coefficient.
Assuming your cubic meters aren't "abnormal", multiply by 60 to get liters per hour, then divide by 1000 to get cubic meters.
If the conditions are different, you may need further adjustments.
what does NL/min?
what is conversion 1 cfm convert to NL/min?
what is conversion 1 m3/min to NL/min.
It is a non-standard abbreviation, not an SI symbol. It is probably meant to mean "normal" liters per minute, where "normal" means that the actual gas volume has been adjusted to what the gas would occupy at 0 °C, 101.325 kPa.
If your cubic meters aren't "abnormal," 1000 L = 1 m³
If your cubic feet aren't "abnormal," 28.317 L per cubic foot
These are geometric conversions and do not account for change of state in the gas.
If your cubic meters or feet are abnormal (ie stated at actual), convert to normal conditions first, then use above for liters. You would need temperature and pressure. If the gas is not approximated well by ideal gas law, you need compressibility factor, virial equation coefficients, or some better equation of state, all of which will depend on gas composition and conditions.