Mixed Air Formula For Combustion

Mixed Air Formula:

\[ \text{Mixed Air} = \text{Fuel Air} + \text{Excess Air} \]

Mixed Air (m³/kg fuel):

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1. What Is Mixed Air Formula For Combustion?

The Mixed Air Formula calculates the total air required for complete combustion of fuel, including both the stoichiometric air (fuel air) and excess air needed to ensure complete combustion and improve combustion efficiency.

2. How Does The Calculator Work?

The calculator uses the mixed air formula:

\[ \text{Mixed Air} = \text{Fuel Air} + \text{Excess Air} \]

Where:

\( \text{Fuel Air} \) — Stoichiometric air required for complete combustion (m³/kg)
\( \text{Excess Air} \) — Additional air beyond stoichiometric requirement (%)
\( \text{Mixed Air} \) — Total air supplied for combustion (m³/kg fuel)

Explanation: The formula ensures complete combustion by providing sufficient oxygen while accounting for practical combustion conditions where excess air is necessary.

3. Importance Of Mixed Air Calculation

Details: Accurate mixed air calculation is crucial for optimizing combustion efficiency, reducing fuel consumption, minimizing emissions, and ensuring complete combustion in industrial processes and power generation.

4. Using The Calculator

Tips: Enter fuel air requirement in m³/kg and excess air percentage. Typical excess air ranges from 10% to 50% depending on the combustion system and fuel type.

5. Frequently Asked Questions (FAQ)

Q1: What is fuel air (stoichiometric air)?
A: Fuel air is the exact amount of air required theoretically for complete combustion of a unit mass of fuel, calculated based on the chemical composition of the fuel.

Q2: Why is excess air necessary?
A: Excess air ensures complete combustion by providing additional oxygen, compensates for imperfect mixing, and helps maintain stable combustion conditions.

Q3: What are typical excess air values?
A: For natural gas: 10-15%, for oil: 15-20%, for coal: 20-30%. Higher values may be needed for poor quality fuels or specific combustion conditions.

Q4: Can too much excess air be problematic?
A: Yes, excessive air can reduce combustion efficiency, increase heat losses, lower flame temperature, and increase NOx emissions.

Q5: How is fuel air calculated for different fuels?
A: Fuel air is calculated based on the chemical formula of the fuel and the stoichiometric oxygen requirement for complete combustion to CO₂ and H₂O.