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The RD-701 is a unique advanced rocket engine configuration incorportating the advantages of tripropellant operation. The engine operates with all three propellants (lox, kerosene, hydrogen) in the booster mode (mode 1) and transitions to bipropellant operation (lox, hydrogen) for the latter portion of the trajectory (mode 2). The hydrogen cooled thrust chamber has three component injector mixing elements with the kerosene element not used in mode 2. In mode 1 operation the hydrogen enhances the combustion of the kerosene to provide to tripropellant specific impulse levels higher than obtainable with separate combustion of the fuels. |
The RD-701 is a fully integrated propulsion unit with two thrust chambers and their associated high pressure turbopumps and preburners incorporated into a thrust frame with common boost pumps, hydraulic system, and pneumatic system. The RD-170 provides the high pressure, oxygen rich powered, lox/kerosene enabling technology for the RD-701, as well as the mature health monitoring and operability systems necessary for the fully reusable, low cost operation envisioned for this engine.
| Advantages of tripopellant configuration: | |
| - | High bulk density propellant for low altitude and high specific impulse for high altitude |
| - | High chamber pressure (power density) with moderate H2 pump pressures |
| - | Hydrocarbon can be stored in wings of vehicle |
| - | H2 available to cool thrust chamber |
| - | Increased combustion efficiency for hydrocarbon |
| - | Improved combustion stability characteristics |
| • | Dimensions | |
| Length of one chamber (in.) | 196.9 | |
| Exit Diameter of the nozzle (in.) | 90.6 | |
| Dry Weight of engine assembly (Ib.) | 9156 | |
| • | Staged combustion power cycle (oxidizer rich) | |
| • | Thrust (SL) (Vacuum) | 714,000/9000,000 Ib. (mode 1) |
| 357,000 Ib. (mode 2) | ||
| • | Isp (SL) (Vacuum) | 330/415 sec. (mode 1) |
| 460 sec. (mode 2) | ||
| • | Throttle | 32-100% |
| • | Oxidizer | Oxygen - Hydrogen |
| • | Fuel | Kerosene (mode 1) |
| Hydrogen (mode 2) | ||
| • | Chamber Pressure | 4,266 psia (mode 1) |
| 1,792 psia (mode 2) | ||
| • | Mixture ratio | |
| (mode 1) | Lox 81.4%, Kerosene 12.6%, Hydrogen 6% | |
| (mode 2) | 6.1 | |
| • | Nozzle Area Ratio | 123.4 |
| • | Preburner | 2 per chamber |
| • | Thrust Chamber Assemblies | 2 |
| • | Ignition | Hypergolic |
В отчете Peter Kramer. MAKS - The Russian/Ukrainian Multi Role Space Transport System. DASA, Munchen, February 1994, приведены следующие параметры двигателя РД-701:
| Параметр | 1-ый режим | 2-ой режим |
| Тяга в вакууме | 2х2000,6 кН | 2х784,5 кН |
| Удельный импульс в вакууме | 4071 с | 4532 с |
| Удельный импульс на старте (М=0.8, Н=10 км) | 3845 с | |
| Расход топлива - О2 | 388,4 кг/с | 148,5 кг/с |
| - Н2 | 29,5 кг/с | 24,7 кг/с |
| - керосин | 73,7 кг/с | |
| Коэффициент расширения | 70/170 | 170 |
| Давление в камере сгорания | 300 бар | 150 бар |
| Максимальный диаметр сопла | 2,4 м | |
| Масса | 1923 кг |
Более подробный рассказ
о конструкции и принципах работы
трехкомпонентного ракетного двигателя РД-701 и
других двигателях для многоразовых космических
систем смотри в мемуарах
Главного конструктора Бориса
Ивановича Губанова (том 3,
глава 40)
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