Table of Contents
- 1 Why high voltage is required in an ignition system?
- 2 What is the output voltage of an ideal ignition exciter of gas turbines?
- 3 What is the component that transfers high voltage supply from the exciter box to the igniter?
- 4 Why is high voltage needed to establish a spark across the gap plug?
- 5 On what voltage in volts does the primary ignition circuit operate?
- 6 What is the main purpose of the turbine nozzle in an aircraft turbine engine?
- 7 Why a simple spark gap Cannot offer full protection against over voltages?
- 8 Why don’t jet engines have igniters all the time?
- 9 Will jet fuel self-ignite when starting a turbine engine?
- 10 How many times do you use continuous ignition in a jet engine?
Why high voltage is required in an ignition system?
In your ignition system, a high-voltage current is required to allow electricity to travel from the spark plug’s center electrode, through the pressurized fuel/ air mixture, and into the side electrode through an electrical arc. This is the premise behind how spark plugs work. to ignition of the air/fuel mixture.
What is the output voltage of an ideal ignition exciter of gas turbines?
Depending on the application, exciter discharge voltages can range from 2,000 volts to over 20,000 volts, discharge current can be unidirectional or oscillatory, and even the shape of the discharge waveform can be modified and controlled.
What is the most common type of spark igniter used on a gas turbine engine?
One disadvantage of this method is that fuel may auto-ignite or otherwise combust before the fuel-air mixture reaches the combustion zone. If this happens the combustor can be seriously damaged. Most igniters in gas turbine applications are electrical spark igniters, similar to automotive spark plugs.
What is the component that transfers high voltage supply from the exciter box to the igniter?
The exciter box sends high-voltage current to the ignition lead, which transfers the high voltage to the igniter.
Why is high voltage needed to establish a spark across the gap plug?
“High voltage from 15,000 volts to 20,000 volts is needed to make the spark.” “It boosts the low voltage in the battery from 12 volts to around 20,000 volts. This high voltage is needed to jump the gap on the spark plugs.”
Why is high voltage needed to establish a spark across the gap of a spark plug?
A voltage surge causes a spark that jumps from lead wire to lead wire across the gap left by the sawing process. These low-cost devices are often used to prevent damaging arcs between the elements of the electron gun(s) within a cathode ray tube (CRT).
On what voltage in volts does the primary ignition circuit operate?
The low voltage primary circuit operates at battery voltage (12 to 14.5 volts) and is responsible for generating the signal to fire the spark plug at the exact right time and sending that signal to the ignition coil. The ignition coil is the component that converts the 12 volt signal into the high 20,000+ volt charge.
What is the main purpose of the turbine nozzle in an aircraft turbine engine?
All gas turbine engines have a nozzle to produce thrust, to conduct the exhaust gases back to the free stream, and to set the mass flow rate through the engine. The nozzle sits downstream of the power turbine. A nozzle is a relatively simple device, just a specially shaped tube through which hot gases flow.
What are four sources of power that we can use to start a turbine engine electrically?
The typical turbine engine is equipped with a capacitor-type, or capacitor discharge, ignition system consisting of two identical independent ignition units operating from a common low-voltage (DC) electrical power source: the aircraft battery, 115AC, or its permanent magnet generator.
Why a simple spark gap Cannot offer full protection against over voltages?
8. Explain why a simple spark gap cannot offer full protection against over voltages. There is no current limiting device provided so as to limit the current after spark over. Hence a series resistance is often used.
Why don’t jet engines have igniters all the time?
Simply put, igniters don’t need to be used all the time in jet engines. Continuous ignition adds undue cost and wear to the critical ignition system. It’s rare for a jet engine to flameout in the first place, and pilots are trained to turn ignition on in situations when there could be a lack of sufficient airflow or fuel into an engine.
What does ignition mean on a jet engine?
Ignition is can be turned on to provide a backup in case internal combustion flames are suddenly extinguished. If pilots receive a low fuel pressure or low fuel quantity, they’re already having a bad day. Turning on the igniters gives the engine a better chance of continually running and providing thrust for its final few minutes.
Will jet fuel self-ignite when starting a turbine engine?
Jet fuel will not self-ignite when starting a modern turbine engine. This articlefrom the WingMag Aviation Magazine says: As the temperature isn’t quite sufficient to initiate self-ignition (the autoignition temperature of aviation fuel is around 220 degrees Celsius), spark plugs are arranged around the combustion chamber.
How many times do you use continuous ignition in a jet engine?
Unlike a piston engine, jet engines are powered by self-sustaining combustion. The igniters in jet engines are used relatively infrequently, but these are 7 times you’ll use continuous ignition… But First… What Exactly Is Continuous Ignition?