Types of Nozzle | Types of Fuel Spray Patterns | How many types of Nozzle ? | Classification of Nozzles | Advantages and Disadvantages of different types of Nozzles | Single hole Nozzle | Multi Hole Nozzle | Circumferential Nozzle | Pintle Nozzle | Pintaux Nozzle |
-:Types of Nozzles/Classification of Nozzles :-
The type of nozzle used is greatly dependent on the type of combustion chamber as open type or pre-combustion chamber .The Nozzles are of following five types -
1- Single hole nozzle
2- Multi-hole nozzle
3- Circumferential nozzle
4- Pintle nozzle
5- Pintaux nozzle
1- Single hole nozzle :- In the single hole nozzle , at the center of the nozzle body there is a single hole which is closed by the nozzle valve . The size of the hole is usually of the order of 0.2 mm . The injection pressure is of order of 8-10 MPa and spray cone angle is about 15⁰ .
Single hole nozzle is the simplest type of nozzle and is used in open combustion chambers .
Advantages of single hole nozzle:- Single hole nozzle is simple in construction and operation .
Disadvantages of single hole nozzle:-
1- Very high injection pressure is required because whole of the fuel passes through a single hole .
2- This type of nozzle has a tendency to dribble .
3- As the spray angle is very narrow , single hole nozzle does not facilitate good mixing unless higher air velocities are provided .
2- Multi-hole nozzle :- Multi hole nozzle consists of a number of holes bored in the tip of the nozzle . The number of holes varies from 4 to 18 and the size from 35 to 200 𝛍𝙢 . The hole angle may be from 20⁰ upwards. These nozzles operate at high injection pressure of the order of 18 MPa. Usually the holes are drilled symmetrically but many times they are non-symmetrical to meet certain specific requirements of the combustion chamber .
Advantages of multi-hole nozzle:-
(i)- Multi-hole nozzle gives good automisation.
(ii)- Multi-hole nozzle distributes fuel properly even with lower air motion available in open combustion chamber .
Disadvantages of multi-hole nozzle:-
(i)- In multi-hole nozzle system , holes are small and liable to clogging .
(ii)- Dribbling between injections occurs in multi-hole nozzle .
(iii)- In multi-hole nozzle , very high injection pressure .
(iv)- In multi-hole nozzle , close tolerance in manufacture and high cost .
3- Circumferential Nozzle :- In circumferential nozzle the injected fuel particles tend to be projected in the form of plane , with wide angle cone , the purpose of which is to obtain as large an area of fuel spray as possible to come into contact with the air in the combustion chamber .
4- Pintle Nozzle :- The stem of the nozzle valve is extended to form a pin or Pintle which protrudes through the mouth of the nozzle body . It may be either cylindrical or conical in shape . The size and shape of the Pintle can be varied according to requirement . The spray core angle is generally 60⁰ . The spray obtained by the Pintle nozzle is hollow conical spray .
Advantages of pintle nozzle:-
(i)- Pintle nozzle is self cleaning type and prevents the carbon deposition on the nozzle hole .
(ii)- Pintle nozzle avoids weak injection and dribbling .
(iii)- Pintle nozzle results in good automisation .
(iv)- The injection characteristics of Pintle nozzle are more near the required one.
Disadvantages of pintle nozzle:- Distribution and penetration is poor in pintle nozzle hence Pintle nozzle is not suitable for open combustion chamber .
5- Pintaux Nozzle :- A Pintaux nozzle is a type of pintle nozzle which has an auxiliary hole drilled in the nozzle body . It injects a small amount of fuel through this additional hole in the upstream slightly before the main injection . The needle valve does not lift fully at low speeds and most of the fuel is injected through the auxiliary hole , giving good cold starting performance .
Disadvantages of Pintaux nozzle :-
(i)- The tendency of the auxiliary hole to choke .
(ii)- The injections characteristics are even poorer then multi -hole nozzle .
-:Types of Nozzles/Classification of Nozzles :-
The type of nozzle used is greatly dependent on the type of combustion chamber as open type or pre-combustion chamber .The Nozzles are of following five types -
1- Single hole nozzle
2- Multi-hole nozzle
3- Circumferential nozzle
4- Pintle nozzle
5- Pintaux nozzle
1- Single hole nozzle :- In the single hole nozzle , at the center of the nozzle body there is a single hole which is closed by the nozzle valve . The size of the hole is usually of the order of 0.2 mm . The injection pressure is of order of 8-10 MPa and spray cone angle is about 15⁰ .
Single hole nozzle is the simplest type of nozzle and is used in open combustion chambers .
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| Single Hole Nozzle , Image Source : Google |
Advantages of single hole nozzle:- Single hole nozzle is simple in construction and operation .
Disadvantages of single hole nozzle:-
1- Very high injection pressure is required because whole of the fuel passes through a single hole .
2- This type of nozzle has a tendency to dribble .
3- As the spray angle is very narrow , single hole nozzle does not facilitate good mixing unless higher air velocities are provided .
2- Multi-hole nozzle :- Multi hole nozzle consists of a number of holes bored in the tip of the nozzle . The number of holes varies from 4 to 18 and the size from 35 to 200 𝛍𝙢 . The hole angle may be from 20⁰ upwards. These nozzles operate at high injection pressure of the order of 18 MPa. Usually the holes are drilled symmetrically but many times they are non-symmetrical to meet certain specific requirements of the combustion chamber .
Advantages of multi-hole nozzle:-
(i)- Multi-hole nozzle gives good automisation.
(ii)- Multi-hole nozzle distributes fuel properly even with lower air motion available in open combustion chamber .
Disadvantages of multi-hole nozzle:-
(i)- In multi-hole nozzle system , holes are small and liable to clogging .
(ii)- Dribbling between injections occurs in multi-hole nozzle .
(iii)- In multi-hole nozzle , very high injection pressure .
(iv)- In multi-hole nozzle , close tolerance in manufacture and high cost .
3- Circumferential Nozzle :- In circumferential nozzle the injected fuel particles tend to be projected in the form of plane , with wide angle cone , the purpose of which is to obtain as large an area of fuel spray as possible to come into contact with the air in the combustion chamber .
4- Pintle Nozzle :- The stem of the nozzle valve is extended to form a pin or Pintle which protrudes through the mouth of the nozzle body . It may be either cylindrical or conical in shape . The size and shape of the Pintle can be varied according to requirement . The spray core angle is generally 60⁰ . The spray obtained by the Pintle nozzle is hollow conical spray .
Advantages of pintle nozzle:-
(i)- Pintle nozzle is self cleaning type and prevents the carbon deposition on the nozzle hole .
(ii)- Pintle nozzle avoids weak injection and dribbling .
(iii)- Pintle nozzle results in good automisation .
(iv)- The injection characteristics of Pintle nozzle are more near the required one.
Disadvantages of pintle nozzle:- Distribution and penetration is poor in pintle nozzle hence Pintle nozzle is not suitable for open combustion chamber .
5- Pintaux Nozzle :- A Pintaux nozzle is a type of pintle nozzle which has an auxiliary hole drilled in the nozzle body . It injects a small amount of fuel through this additional hole in the upstream slightly before the main injection . The needle valve does not lift fully at low speeds and most of the fuel is injected through the auxiliary hole , giving good cold starting performance .
Disadvantages of Pintaux nozzle :-
(i)- The tendency of the auxiliary hole to choke .
(ii)- The injections characteristics are even poorer then multi -hole nozzle .
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