1、SAE AIRx784C 95 = 7943725 0535007 984 AEROSPACE INFORMATION The Engineering Society eA For Advancing Mobility Land Sea Air and Space INTERNATIONAL 400 Commonwealth Drive, Warrendale, PA 15096-0001 R E Po RT Submitted for recognition as an American National Standard Issued 1963-07 Revised 1995-06 INT
2、ERRELATION OF ENGINE DESIGN AND BURNER CONFIGURATION WITH SELECTION AND PERFORMANCE OF ELECTRICAL IGNITION SYSTEMS FOR GAS TURBINE ENGINES 1. SCOPE: To describe typical ignition systems in general usage and their parameters that warrant consideration during the development of a gas turbine engine. T
3、o describe those parameters in gas turbine engine design and, in particular, burner configurations that influence the type selection and performance of the ignition system. To indicate the areas where future work may uncover important effects having a direct bearing on certain interrelated parameter
4、s, with resultant benefits to both the engine and ignition designers. 1.1 Purpose: To provide the designer of gas turbine engines with a working knowledge of the interrelation between engine performance objectives and the pari played by ignition in meeting the objectives. To present a definitive col
5、lection of standard references, nomenclature, and descriptive terminology sufficient to provide a basis for design approach in specification of gas turbine ignition systems. To stimulate further work necessary in the development of knowledge of the unknown, interrelated parameters. SAE Technical Sta
6、ndards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use. including any patent infringement arising therefrom, is the sole r
7、esponsibility of the user.“ SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 1995 Society of Automotive Engineers, Inc. AI1 rights reserved. Printed in U.S.A. SAE AIR*?8
8、4C 75 7743725 0535008 ALO SAE AIR784 Revision C 2. REFERENCES: 2.1 Applicable Documents: The following publications form a part of this specification to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in eff
9、ect on the date of the purchase order. In the event of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 2.1.
10、1 SAE Publications: Available from SAE, 400 Commonwealth Drive, Warrendale, PA 2.2 15096-0001. ARP484 Spark Igniter Gap Types ARP846 Low Tension Spark Igniter Sparking Voltage Test Related Publications: The following publications are provided for information purposes only and are not a required part
11、 of this document. Al R77 Al R84 ARP294 ARP295 AS422 AS423 ARP424 AS453 ARP494 ARP504 ARP670 AS692 AIR801 AS803 AS81 4 ARP841 AIR885 AIR1090 AIR1 O91 AIR1092 AIR1423 Spark Energy Measuring Using Oscilloscopic Methods Ignition Peak Voltage Measurements Terminal, Lead, Low Voltage Igniter Plug Termina
12、l Well, Low Voltage Igniter Plug Spark Igniter Outline - Right Angle Flange Mounting Spark Igniter Outline - Flange Mounting Spark Igniter Outline, Threaded Mounting Abbreviations Gasket Terminals - Input - Ignition Exciters Ignition System Testing - Metering and Power Supplies Terminal, Aircraft Ig
13、nition Igniter, Spark, Aeronautical Engine (High Tension) Oscillographic Method for Measuring Spark Energy of Capacitor Discharge Ignition Systems Igniter, Spark, Aeronautical Engine (Low Tension) Spark Igniter Outline - .750-20 Threaded Mounting Leads Flexible, Shielded, High Energy Ignition The Sp
14、ark Calorimeter Ignition Exciter Output Voltage Pulse Measurement Using a Pressurized Ball Gap High Voltage Pulse Generator High Tension Exciter Output Voltage Measurement Using Cathode-Ray Oscilloscope Electromagnetic Compatibility on Gas Turbine Engines for Aircraft Propulsion SA AIR784 Revision C
15、 2.2 (Continued): RTCNDO-160 MI L-STD-461 MIL-STD-462 MIL-STD-704 MIL-STD-81 O MIL-STD-826 MIL-STD-1818 MI L-E-5007 MI L-E-5009 MI L-E-8593 MI L-E-8595 MIL-E-8597 MIL-P-8686 AN-I-27a MIL-1-61 81 MI L-1-26600 Environmental Conditions and Test Procedures for Airborne Equipment Electromagnetic Interfer
16、ence Characteristics Requirements for Equipment Electromagnetic Interference Characteristics, Measurement of Electric Power Aircraft, Characteristics and Utilization of Environmental Test Methods Electromagnetic Interference Test Requirements and Test Methods Electromagnetic Effects Requirements for
17、 Systems Engines, Aircraft, Turbojet, General Specifications for Engines, Aircraft, Turbojet, Qualification Test for Engines, Aircraft, Turboprop, General Specifications for Engines, Aircraft, Turboprop, Qualification Test for Engines, Aircraft, Experimental Turboprop Preliminary Flight Rating Test
18、for Power Units; Aircraft Auxiliary, Gas-Turbine Type, General Specification for Interference Limits; Aircraft and Vehicular Engine Radio Interference Limits, Tests and Design Requirements, Aircraft Electrical and Electronic Equipment Interference Control Requirements, Aeronautical Equipment 3. GLOS
19、SARY OF TERMS: 3.1 Spark Igniters: 3.1.1 High Tension: Defined as, “An item incorporating an electrode(s) across which an electric spark is discharged to ignite a combustible mixture in a continuous burning cycle engine and categorized by “high voltage air gap, high voltage surface gap, and high vol
20、tage air surface gap” by ARP484. This type requires more than 5 kV potential to create a spark between the electrodes. 3.1.2 Low Tension: Defined same as 3.1 .I and categorized by “shunted surface gap” in ARP484. This type requires less than 5 kV potential to create a spark between the electrodes. G
21、eneral practice dictates that a “new” spark igniter shall spark when 1 O00 V is applied, per ARP846. -3- SAE AIR*784C 95 7943725 0535030 479 SAE AIR784 Revision C 3.2 Ignition Leads: 3.2.1 High Tension: Defined as, “A definite length of electrical cable having at least one end terminated in a single
22、, common fitting.” Its construction, materials used, etc. must be such as to conduct the discharge energy from a high tension ignition exciter (in excess of 5 kV) to a high tension spark igniter. 3.2.2 Low Tension: Defined same as 3.2.1, but designed to conduct the discharge energy from a low tensio
23、n ignition exciter (less than 5 kV) to a low tension spark igniter. 3.3 3.4 3.5 3.6 3.7 3.8 3.9 Ignition Exciter: An assembly of component parts which provides a means of changing low voltage alternating current or low voltage direct current to a condition suitable to provide (with or without additi
24、onal devices) a spark discharge for ignition purposes. Capacitor Discharge System: An ignition system in which the spark energy is primarily the result of a capacitor discharge. (See 4.1, 4.2, and 4.5 for illustrations of typical system circuits.) Inductive System: An ignition system in which the sp
25、ark energy is primarily the result of a rapid variation in magnetic flux in an induction coil. (See 4.3 for illustration of a typical system circuit.) Spark Energy: The energy (joules) released between electrodes of the spark igniter. Spark Rate: The number of spark discharges per unit time occurrin
26、g at the spark igniter under a given set of conditions. (Example: 2 sparks per second minimum at room temperature and 24 V DC input.) “Usually the spark rate is specified as a minimum figure at the lowest input voltage to control the minimum number of sparks in the worst case condition and a maximum
27、 value at the highest input voltage to control the life of the spark igniter.” Spark Duration: The length of time usually expressed in microseconds, required to dissipate the total energy of any one spark discharge occurring between the electrodes of a spark igniter. Stored Energy: The energy (joule
28、s) stored in the tank or storage capacitor of a capacitor discharge system (1/2 CE2), or in the inductance coil of an inductive discharge system (112 LI). -4- SAE AIR*784C 75 7743725 0535033 305 H SAE AIR784 Revision C 3.1 O 3.1 1 3.1 2 3.1 3 4. 4. Duty Cycle: The operating cycle required of the ign
29、ition system. It is expressed as a function of time ON and time OFF or continuous, as applicable , and is generally associated with the ignition exciter specification. High Tension Systems: Ignition systems capable of delivering voltages in excess of 5 kV to the firing tip of the spark igniter. Low
30、Tension System: Ignition systems capable of delivering voltages up to 5 kV inclusive to the firing tip of the spark igniter. Self-contained System: Ignition systems meeting one or more of the other definitions herein which, in addition, are designed to operate from a power source which is engine sup
31、plied equipment. TYPICAL IGNITION SYSTEM CIRCUITS: The following simplified ignition circuits are shown to illustrate the basic components that establish the system limitations. These are to assist the engine designer in the realization for the need of zoning the system components on the engine in r
32、egard to temperature, vibration, distribution efficiency, etc. DC Capacitor Discharge System, High Tension (See Figure 1): Comments: The high tension capacitor discharge system produces an initial ionizing voltage of a magnitude as large as necessary (within design limits) to ionize the gap of the h
33、igh tension spark igniter. This ionizing voltage usually has the waveform of a very short duration pulse or “spike” (above 5 kV as compared with the remainder of the discharge voltage (O to 500 V). Because of the high magnitude of the ionizing voltage, a wide variety of spark igniter gap geometries
34、are compatible with this system. The ionized spark igniter gap provides the necessary low impedance path for the discharge of the energy stored in the storage capacitor, through the ionized spark discharge gap, secondary winding of the high frequency transformer coil, high tension ignition lead, cen
35、ter electrode of the spark igniter, and arc to ground. Because relatively large amounts of energy are thus expended in the resulting spark in a matter of microseconds, the heat release and the accompanying shock wave to fuel-air mixtures is sufficient to produce ignition over a wide range of combust
36、ion conditions. Detailed explanations of the electrical phenomena of ignition circuits such as illustrated in Figure 1 are available in many publications and in manufacturers literature. -5- SAE AIR*784C 75 7943725 0535032 243 m SAE AIR784 Revision C 4.1 4.2 (Continued): For the purposes of this doc
37、ument, the following observations are made concerning the high tension version of the capacitor discharge system: a. It is usually the heaviest, and largest, of the three basic ignition circuits discussed in this document, due to the incorporation of the high frequency transformer coil and its high
38、frequency capacitor. The high frequency transformer coil itself causes certain energy losses and alters the time duration and peak power level of the spark from that which would be obtained if the coil were not present. Use of such a coil may therefore necessitate higher stored energy requirements.
39、b. The high voltages demanded by the spark igniter under extremes of high pressure and electrode erosion must be considered in the determination of acceptable ambient temperatures and altitudes, lead lengths, terminal configuration, cable insulation, and the design of the spark igniter. DC Capacitor
40、 Discharge System, Low Tension (See Figure 2): Comments: The low tension capacitor discharge system produces sufficient voltage to cause current to flow across a semi-conductive surface in intimate contact with the center electrode and ground shell of a low tension spark igniter. This initial flow o
41、f current ionizes the air between the center electrode and the ground shell so that the energy stored in the storage capacitor discharges through the ionized spark gap, the low tension ignition lead, the center electrode of the spark igniter, to ground. Because relatively large amounts of energy are
42、 thus expended in the resulting spark in a matter of microseconds, the heat release, and the accompanying shock wave, to fuel-air mixtures is sufficient to produce ignition over a wide range of combustible mixtures. Detailed explanations of the electrical phenomena of ignition circuits such as illus
43、trated in Figure 2 are available in many publications and in manufacturers literature. For the purposes of this document, the following observations are made concerning the low tension version of the capacitor discharge system: a. Because the low tension spark igniter firing tip contains its own shu
44、nted surface (semi- conductor body), contamination of the electrodes by fuel, carbon, or other combustion residues has little effect on the generation of a spark. For the same reason, higher burner pressures may be ignited than are feasible in the air gap or surface gap types of high tension spark i
45、gniters. -6- SAE AIR*784C 95 m 7743725 0535033 388 m SAE AIR784 Revision C 4.2 4.3 (Continued): b. Lacking the inductance of a high frequency transformer coil in the discharge circuit, the spark duration is shorter and the peak power of the first pulse on the spark train is higher. This concentratio
46、n of heat in the spark is more effective under some combustion conditions, which could result in lower stored energies and resultant decreases in the system weight and size. c. Lower discharge voltages permit smaller cable insulation, lighter leads, and are more easily controllable under extremes of
47、 ambient temperature and altitude. d. Because the functioning of the entire system depends on the condition of the semi-conductor surface required in the firing tip of the spark igniters, they may be influenced by engine burner conditions and may require more frequent replacement than do air gap or
48、surface gap types of high tension spark igniters. The necessity of maintaining intimate contact between the electrodes and the semi-conductor material requires that particular attention be given to the extremes of temperature to which the firing tip is subjected. Each system application must be stud
49、ied for its peculiar conditions. Inductive System (See Figure 3): Comments: The inductive discharge system is similar in performance to the magneto or battery timer ignition used on reciprocating engines. It is usually the lightest, smallest, and least expensive of all three basic circuits considered in this document. It produces a high voltage inductive spark shower in frequency with the rate of opening of the contact points. For the purpose of this document, the following observations are noted: a. It contains fewer electrical components than are necessary in the other ignition s
