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System analysis of jet engines of high supersonic flight velocities
Aerospace
Science
and Technology, 1997, no 3, 179-182
System Analysis of Jet Engines of High Supersonic Flight Velocities V. V. Kozlaykov V. V. Kozlaykov, Ph. D. Moscow State Aviation Institute, 4, Volokolamskoe Highway, Moscow A-80, 125871 Russia.
Manuscript received May 29, 1995; revised version November 23, 1995.
Kozlaykov V. V., Aerospace Science and Technology,
1997, no 3, 179-182.
Combined jet engines concept have evolved from the rocket and the two basic air-breathing types: (1) the turbojet, and (2) the ramjet. Unlike the turbojet and ramjet, which has atmospheric air as an oxidizer, the rocket carries its own oxidizer as well as its own fuel. In Figure 1, combined jet engines concepts is presented [l].
Abstract
There are combined cycle concepts based on any two and all three of the basic types. At present, a great number of different schemes of combined jet engines, working on cryogenic fuel [2], is known. Therefore, the development of classification of such engines is very timely.
I - INTRODUCTION The most widespread method of the classification is hierarchical one but it does not cover all schemes of combined jet engines. A method is known [3], which is based on a natural classification of a multitude of flight vehicles according to the kind and family of forces used, and types of engines creating these forces. The basic of classification structure consists of the interaction of forces, acting on the flight vehicle, and “sorts” of propulsion. The ordering is based on the “primary-secondary” criterion. In the work [4], the classification is based on the assumption that the thrust is a common property of all engines and the specificity of its creation in each engine permits to distinguish the classes and types of engines. But the engine as such is considered to be a “black box” in which the internal processes concerning the mass and energy (i.e., the processes of release of the energy, its transformation and interaction with the mass) are not taken into account. In Figure 2, a model of the combined air-breathing jet engine is presented. The working process of this engine consists of two cycles: the generator cycle, serving to provide useful work and produce energy, transferred to working fluid, taking part in the main cycle, and the main cycle, in which the supplied energy is converted into the useful work. The main spool can be conditionally conceived as a Aerospace
Science and Technology,
0034-1223,
97/03/$ 7.00/O
Gauthier-Villars
device for air flow compression and energy conversion into the useful work for producing the thrust. The effectiveness of a combined jet engine is determined by the manner and perfection of energy transfer. The marginal combined jet engines, which define the limits of applicability of the generalised model, are the afterburning gas-turbine jet engines and liquidair cycle engines. In afterburning gas-turbine jet engine, a power unit can be distinguished, which Turbojet engine
Rocket Fig.
Ramjet engine
engine
1. - Combined
jet engines
concepts.
180
V. V. Kozlaykov Table
2. - Examples
Types
of coding
of
Afterbuning
the combined
engine
gas-turbine
air-breathing
jet engine.
Xassificatiar attribute vector code
ialue of class Ni
jet
1111
1131
Fig. 2. - Generalised
model
of the combined
air-breathing
Turborocket
engine
Turborocket
ramjet
works according to the Brayton cycle and represents a turbocompressor system, where a conditional line, separating it from the main coutour, goes through the compressor and is defined by the equality of pressures behind the turbine and at. In the liquid-air cycle engine, the power unit works according to the Renkine cycle (rocket cycle), combined with the Brayton cycle making up a hybrid cycle. In this work, construction of classification of combined jet engine, working on cryogenic fuel, is based on four main principles of mass- and energy transfer between the main spool and the power unit.
Rocket
ramjet
OF SYSTEM
1.
- Principles
Classification
engine
engine
cycle
of the classification
of hydrogen
combined
of energy transfer [2]. The marginal combined jet engines, which define the limits of applicability of the generalised model, are the afterburning gas-turbine jet engines and liquid-air-cycle engines. System analysis of combined jet engine, working on cryogenic fuel, air-breathing
attribute
of the energy in gas-generator
3 3 13
engine
Alternative
jet engines.
value
of attribute
I
1. Principle conversion
2332
ANALYSIS
The working process of these engines consists of two cycles: (1) the general cycle, serving to provide useful work, and produce energy, transferred to working fluid, taking part in the main cycle, and (2) the main cycle, in which the supplied energy is converted into the useful work. The effectiveness of combined jet engine is determined by the manner and perfection Table
2222
yjpj
Liquid-air Inlet
II - METHOD
AB
jet engine.
Brayton
cycle
(air cycle)
-Yt I
Renkine
cycle
(rocket
cycle)
Hybrid
cycle
cycle
2. Principle of generator cycle energy transfer to main cycle
With taking off the mechanical work but without off the thermal energy
With taking off the mechanical work and thermal energy
With taking off the thermal energy without taking off mechanical work
3. Principle of additing of generator cycle mass to the main cycle
Without
mass addition
With the addition of mass but without the increase of kinetic energy
With the addition of mass and increase of kinetic energy
4. Principle of using the energy source properties in the generator cycle
Calorific
value
Calorific capacity
Calorific value, cooling and working capacity
value
and working
Aerospace
Science
capacity
and Technology
System Analysis of Jet Engines of High Supersonic
Flight Velocities
181
Such an approach to the system analysis permits for any scheme of combined jet engine to unambiguously define the code of classification attribute vectors as a four-digit number. The coding is performed in accordance with Table 1. In this code, the number order determines the classification attribute and the number value - the number of the column of alternative meaning of attribute. The class of engine is coded in the one-dimensional classification field according to the code of classificaton attribute vectors using the formula:
n-1
Cj Main
Fig.
3. - “Hybrid&s
spool degree”
<---
--->
Power
of a number
of known
unit
j=i+l
schemes.
is based on four main principles of mass- and energy transfer between the main spool and the power unit, namely: (1) the principle of energy conversion in the gas generator cycle; (2) the principle of energy transfer from the generator cycle to the main cycle; (3) the principle of adding the mass of generator cycle to that of main spool; (4) the principle of using main properties of energy source in the generator cycle [5]. Such classification attribute has three alternative meaning, which are given in Table 1 in the columns with ordinal numbers Yt, assuming the values 1, 2, 3. Table 3. ~ Table jet engines.
of multitude
n
N=ci=l(pi),- 1))fl tj +(qcn,
of technical
decisions
for combined
where Yt = 1,3 - the value of number placed in 1st position of code of the attribute class vectors; t - ordinal number of the value in the classification attribute vector code; 1: = 1, n - number of 4th position of vector code. The examples of the determination of vector codes of classification attributes and class are presented in Table 2. For instance, for the code of classification attribute vector is equal to 2232 and its class is determined in such a manner:
N=
(2-1)*33+(2-1)*32+(3-1)~31+2=44.
The value of class of combined engines of any scheme changes from 1 (gas-turbine engine) to 81 (liquidair cycle engine). The notion “hybridness degree” C, = N/81 can be introduced. It determines the ratio of class number N to its limiting value equal to 81 for liquid-air cycle engine. The value of engine “hybridises degree” changes within the range from a number close to zero (afterburning gas-turbine jet engine). In Figure 3, the example of classes and “hybridises degree” of a number of known schemes are presented. Higher value of the “hybridises degree” shows that useful work of the combined jet engine cycle is created to a greater extent by the power unit than by the main spool.
III - CONCLUSION The proposed approach to the classification of combined hydrogen jet engine permits to systematise al schemes of engines of a given class according to the working process and is a good basic for the development of new schemes of such engines (Table 3) [6]. 1997. no 3
V. V. Kozlaykov
182
REFERENCES [l] Kors D. L. - Combined Cycle Propulsion for Hypersonic Flight, Actu Astronaut, 1988, N18, 191200. [2] Kurziner R. I. - Jet Engines of Great Supersonic Flight Velocities, M. Mashinostroenie, 1989, 264 p. [3] Guryanov M. A. - Classification of Flight Vehicles According to the Kind of Propulsion, Izv. Vuz’ov, Aviatsionnaia Tehnika, 1985, N4, 33-39. [4] Fishbein B. 0. - On the Construction of Classification of Flight Vehicles. Zz. Vuz’ov, Aviatsionnaia Tehnika, 1989, Nl, 70-74.
[5] Kozlaykov V. V. - Classification Problems of Combined Air Breathing-Rocket Propulsion Systems for Fly at Great Speeds. Proceedings of second Russian-Chinese scientific conference “Aero- and space engines and power planes”. September-October, 1992, Moscow (in Russian), 297. [6] Kozlaykov V. V., Kravchenko I. V. - Classification of Combined Air Breathing-Rocked Engines Using Hydrogen. Abstracts of International Aerospace Congress, August L-19, Moscow, Russia, 320.
Aerospace
Science
and Technology
Science
and Technology, 1997, no 3, 179-182
System Analysis of Jet Engines of High Supersonic Flight Velocities V. V. Kozlaykov V. V. Kozlaykov, Ph. D. Moscow State Aviation Institute, 4, Volokolamskoe Highway, Moscow A-80, 125871 Russia.
Manuscript received May 29, 1995; revised version November 23, 1995.
Kozlaykov V. V., Aerospace Science and Technology,
1997, no 3, 179-182.
Combined jet engines concept have evolved from the rocket and the two basic air-breathing types: (1) the turbojet, and (2) the ramjet. Unlike the turbojet and ramjet, which has atmospheric air as an oxidizer, the rocket carries its own oxidizer as well as its own fuel. In Figure 1, combined jet engines concepts is presented [l].
Abstract
There are combined cycle concepts based on any two and all three of the basic types. At present, a great number of different schemes of combined jet engines, working on cryogenic fuel [2], is known. Therefore, the development of classification of such engines is very timely.
I - INTRODUCTION The most widespread method of the classification is hierarchical one but it does not cover all schemes of combined jet engines. A method is known [3], which is based on a natural classification of a multitude of flight vehicles according to the kind and family of forces used, and types of engines creating these forces. The basic of classification structure consists of the interaction of forces, acting on the flight vehicle, and “sorts” of propulsion. The ordering is based on the “primary-secondary” criterion. In the work [4], the classification is based on the assumption that the thrust is a common property of all engines and the specificity of its creation in each engine permits to distinguish the classes and types of engines. But the engine as such is considered to be a “black box” in which the internal processes concerning the mass and energy (i.e., the processes of release of the energy, its transformation and interaction with the mass) are not taken into account. In Figure 2, a model of the combined air-breathing jet engine is presented. The working process of this engine consists of two cycles: the generator cycle, serving to provide useful work and produce energy, transferred to working fluid, taking part in the main cycle, and the main cycle, in which the supplied energy is converted into the useful work. The main spool can be conditionally conceived as a Aerospace
Science and Technology,
0034-1223,
97/03/$ 7.00/O
Gauthier-Villars
device for air flow compression and energy conversion into the useful work for producing the thrust. The effectiveness of a combined jet engine is determined by the manner and perfection of energy transfer. The marginal combined jet engines, which define the limits of applicability of the generalised model, are the afterburning gas-turbine jet engines and liquidair cycle engines. In afterburning gas-turbine jet engine, a power unit can be distinguished, which Turbojet engine
Rocket Fig.
Ramjet engine
engine
1. - Combined
jet engines
concepts.
180
V. V. Kozlaykov Table
2. - Examples
Types
of coding
of
Afterbuning
the combined
engine
gas-turbine
air-breathing
jet engine.
Xassificatiar attribute vector code
ialue of class Ni
jet
1111
1131
Fig. 2. - Generalised
model
of the combined
air-breathing
Turborocket
engine
Turborocket
ramjet
works according to the Brayton cycle and represents a turbocompressor system, where a conditional line, separating it from the main coutour, goes through the compressor and is defined by the equality of pressures behind the turbine and at. In the liquid-air cycle engine, the power unit works according to the Renkine cycle (rocket cycle), combined with the Brayton cycle making up a hybrid cycle. In this work, construction of classification of combined jet engine, working on cryogenic fuel, is based on four main principles of mass- and energy transfer between the main spool and the power unit.
Rocket
ramjet
OF SYSTEM
1.
- Principles
Classification
engine
engine
cycle
of the classification
of hydrogen
combined
of energy transfer [2]. The marginal combined jet engines, which define the limits of applicability of the generalised model, are the afterburning gas-turbine jet engines and liquid-air-cycle engines. System analysis of combined jet engine, working on cryogenic fuel, air-breathing
attribute
of the energy in gas-generator
3 3 13
engine
Alternative
jet engines.
value
of attribute
I
1. Principle conversion
2332
ANALYSIS
The working process of these engines consists of two cycles: (1) the general cycle, serving to provide useful work, and produce energy, transferred to working fluid, taking part in the main cycle, and (2) the main cycle, in which the supplied energy is converted into the useful work. The effectiveness of combined jet engine is determined by the manner and perfection Table
2222
yjpj
Liquid-air Inlet
II - METHOD
AB
jet engine.
Brayton
cycle
(air cycle)
-Yt I
Renkine
cycle
(rocket
cycle)
Hybrid
cycle
cycle
2. Principle of generator cycle energy transfer to main cycle
With taking off the mechanical work but without off the thermal energy
With taking off the mechanical work and thermal energy
With taking off the thermal energy without taking off mechanical work
3. Principle of additing of generator cycle mass to the main cycle
Without
mass addition
With the addition of mass but without the increase of kinetic energy
With the addition of mass and increase of kinetic energy
4. Principle of using the energy source properties in the generator cycle
Calorific
value
Calorific capacity
Calorific value, cooling and working capacity
value
and working
Aerospace
Science
capacity
and Technology
System Analysis of Jet Engines of High Supersonic
Flight Velocities
181
Such an approach to the system analysis permits for any scheme of combined jet engine to unambiguously define the code of classification attribute vectors as a four-digit number. The coding is performed in accordance with Table 1. In this code, the number order determines the classification attribute and the number value - the number of the column of alternative meaning of attribute. The class of engine is coded in the one-dimensional classification field according to the code of classificaton attribute vectors using the formula:
n-1
Cj Main
Fig.
3. - “Hybrid&s
spool degree”
<---
--->
Power
of a number
of known
unit
j=i+l
schemes.
is based on four main principles of mass- and energy transfer between the main spool and the power unit, namely: (1) the principle of energy conversion in the gas generator cycle; (2) the principle of energy transfer from the generator cycle to the main cycle; (3) the principle of adding the mass of generator cycle to that of main spool; (4) the principle of using main properties of energy source in the generator cycle [5]. Such classification attribute has three alternative meaning, which are given in Table 1 in the columns with ordinal numbers Yt, assuming the values 1, 2, 3. Table 3. ~ Table jet engines.
of multitude
n
N=ci=l(pi),- 1))fl tj +(qcn,
of technical
decisions
for combined
where Yt = 1,3 - the value of number placed in 1st position of code of the attribute class vectors; t - ordinal number of the value in the classification attribute vector code; 1: = 1, n - number of 4th position of vector code. The examples of the determination of vector codes of classification attributes and class are presented in Table 2. For instance, for the code of classification attribute vector is equal to 2232 and its class is determined in such a manner:
N=
(2-1)*33+(2-1)*32+(3-1)~31+2=44.
The value of class of combined engines of any scheme changes from 1 (gas-turbine engine) to 81 (liquidair cycle engine). The notion “hybridness degree” C, = N/81 can be introduced. It determines the ratio of class number N to its limiting value equal to 81 for liquid-air cycle engine. The value of engine “hybridises degree” changes within the range from a number close to zero (afterburning gas-turbine jet engine). In Figure 3, the example of classes and “hybridises degree” of a number of known schemes are presented. Higher value of the “hybridises degree” shows that useful work of the combined jet engine cycle is created to a greater extent by the power unit than by the main spool.
III - CONCLUSION The proposed approach to the classification of combined hydrogen jet engine permits to systematise al schemes of engines of a given class according to the working process and is a good basic for the development of new schemes of such engines (Table 3) [6]. 1997. no 3
V. V. Kozlaykov
182
REFERENCES [l] Kors D. L. - Combined Cycle Propulsion for Hypersonic Flight, Actu Astronaut, 1988, N18, 191200. [2] Kurziner R. I. - Jet Engines of Great Supersonic Flight Velocities, M. Mashinostroenie, 1989, 264 p. [3] Guryanov M. A. - Classification of Flight Vehicles According to the Kind of Propulsion, Izv. Vuz’ov, Aviatsionnaia Tehnika, 1985, N4, 33-39. [4] Fishbein B. 0. - On the Construction of Classification of Flight Vehicles. Zz. Vuz’ov, Aviatsionnaia Tehnika, 1989, Nl, 70-74.
[5] Kozlaykov V. V. - Classification Problems of Combined Air Breathing-Rocket Propulsion Systems for Fly at Great Speeds. Proceedings of second Russian-Chinese scientific conference “Aero- and space engines and power planes”. September-October, 1992, Moscow (in Russian), 297. [6] Kozlaykov V. V., Kravchenko I. V. - Classification of Combined Air Breathing-Rocked Engines Using Hydrogen. Abstracts of International Aerospace Congress, August L-19, Moscow, Russia, 320.
Aerospace
Science
and Technology