Fuels Properties

Overview

Engineering reference data for Fuels Properties in combustion engineering.

Key Formulas

Heat Release

$Q = \dot{m} \cdot HV$

Fuel energy release rate.

Air-Fuel Ratio

$AF = \frac{m_{air}}{m_{fuel}}$

Mass of air per mass of fuel.

Excess Air

$EA = \frac{O_2}{21 - O_2} \times 100\%$

From flue gas oxygen measurement.

Variables

Key Properties of Petroleum-Based Fuels

Petroleum-based fuels are characterized by several critical properties that determine their performance, handling, and emissions. The primary fuels include gasoline, diesel, jet fuel, and fuel oil.

• Density and Specific Gravity: The mass per unit volume (e.g., kg/m³). It affects energy content per volume and is a key measurement for fuel quality and custody transfer.
• Viscosity: A measure of a fluid's resistance to flow. Critical for fuel injection and atomization in engines; too high a viscosity can lead to poor combustion.
• Flash Point: The lowest temperature at which the fuel can vaporize to form an ignitable mixture in air. A primary safety characteristic for storage and handling.
• Cetane Number (Diesel) / Octane Rating (Gasoline): Measures of combustion quality. Cetane indicates diesel's ignition delay (higher is better), while octane indicates gasoline's resistance to knock (higher is better).
• Heating Value (Calorific Value): The amount of energy released per unit mass (specific energy) or volume during complete combustion. The Lower Heating Value (LHV) assumes water in the combustion products remains vapor, which is the typical standard for engine performance calculations.
• Pour Point: The lowest temperature at which the fuel will flow. Important for cold weather operation.
• Sulfur Content: Regulated due to its role in forming sulfur oxides (SOx) emissions, which cause acid rain and poison catalytic converters.

For detailed, standardized property data, consult the referenced database: AFDC Fuels Properties.

References

• Original Source