This lecture discusses the basic process of combustion of liquid fuels

1. z
Combustion of
liquid fuels
Lecture 10
By
Er. T. AYISHA NAZIBA, Dr. D. RAMESH, Dr.S. PUGALENDHI, Dept. of
REE, AEC & RI, TNAU, Coimbatore-03

2. z
Combustion of liquid fuels
 Combustion of liquids is a complex process that involves several stages.
 The first stage is atomization, which is the process of breaking up a liquid
into small droplets. This is typically done using a spray nozzle, which forces
the liquid through a small orifice at high pressure. The smaller the droplets,
the greater the surface area to volume ratio, which means that they will
evaporate more quickly.
 The second stage is evaporation, which is the process of converting a liquid
into a gas. The rate of evaporation depends on the temperature of the
droplets, the surrounding air, and the vapor pressure of the liquid. As the
droplets evaporate, they cool the surrounding air. This can lead to a
phenomenon known as flame quenching, which is the extinction of a flame
due to a lack of heat

3. z
 The third stage is mixing, which is the process of bringing the
fuel vapor into contact with the oxidizer, which is typically air.
The rate of mixing depends on the turbulence of the air and the
size of the droplets. As the fuel vapor and air mix, they form a
combustible mixture.
 The fourth stage is ignition, which is the process of starting the
combustion reaction. The ignition temperature is the minimum
temperature at which the combustion reaction will occur. The
ignition temperature depends on the fuel, the oxidizer, and the
mixture ratio. Once the mixture is ignited, the combustion
reaction will continue until all of the fuel has been consumed

4. z

5. z
Atomization
Atomization is the process of breaking up a liquid into small droplets. This is
typically done using a spray nozzle, which forces the liquid through a small
orifice at high pressure. The smaller the droplets, the greater the surface
area to volume ratio, which means that they will evaporate more quickly.

6. z
Evaporation
 Evaporation is the process of converting a liquid into a gas. The
rate of evaporation depends on the temperature of the droplets,
the surrounding air, and the vapor pressure of the liquid. As the
droplets evaporate, they cool the surrounding air. This can lead
to a phenomenon known as flame quenching, which is the
extinction of a flame due to a lack of heat

7. z
Mixing and Ignition
 Mixing is the process of bringing the fuel vapor into contact with the
oxidizer, which is typically air. The rate of mixing depends on the
turbulence of the air and the size of the droplets. As the fuel vapor
and air mix, they form a combustible mixture.
 Ignition is the process of starting the combustion reaction. The
ignition temperature is the minimum temperature at which the
combustion reaction will occur. The ignition temperature depends
on the fuel, the oxidizer, and the mixture ratio. Once the mixture is
ignited, the combustion reaction will continue until all of the fuel has
been consumed.

8. z
Droplet
 A droplet is a small, spherical particle
of liquid. Droplets are formed when a
liquid is atomized. The size of a
droplet depends on the type of spray
nozzle and the pressure of the liquid

9. z