If 1 cubic foot of natural gas is 1000 Btuh, what is the ratio of dilution air?

In combustion systems, dilution air is typically mixed with the fuel gas before ignition. The ratio of dilution air to fuel gas is crucial for ensuring complete combustion and maintaining safe operation.

For natural gas, a commonly accepted practice for calculating the dilution air ratio is based on the heating value of the gas and the desired air-fuel mixture. In this context, when 1 cubic foot of natural gas is stated to produce 1000 Btuh, it indicates the energy released when that volume of gas combusts.

The correct ratio of dilution air is determined by the ideal stoichiometric combustion conditions, which require a specific amount of air to fully combust a unit volume of gas. The value of 15 signifies that for every part of the natural gas, 15 parts of air are required for complete and efficient combustion. This ratio helps to ensure that there is enough air to mix with the gas, preventing issues like incomplete combustion, which could lead to the production of carbon monoxide and other harmful byproducts.

Thus, a ratio of 15 for dilution air indicates a safe and effective combustion mixture for 1 cubic foot of natural gas at 1000 Btuh, aligning with common combustion practices in heating applications.