manu/mldr-zoomed-100char-total-queries-documents

chunk_id stringlengths 3 9	chunk stringlengths 1 100
9828_74	wheel, the gas was redirected through a ring of stator blades and enters the second stage turbine
9828_75	wheel. The gas left the turbine through the exhaust ducting. Three dynamic seals in series
9828_76	prevented the pump fluid and turbine gas from mixing. Power from the turbine was transmitted to the
9828_77	pump by means of a one-piece shaft.
9828_78	Oxidizer turbopump
9828_79	The oxidizer turbopump was mounted on the thrust chamber diametrically opposite the fuel turbopump.
9828_80	It was a single-stage centrifugal pump with direct turbine drive. The oxidizer turbopump increases
9828_81	the pressure of the LOX and pumps it through high-pressure ducts to the thrust chamber. The pump
9828_82	operated at 8,600 rpm at a discharge pressure of (absolute) and developed . The pump and its two
9828_83	turbine wheels are mounted on a common shaft. Power for operating the oxidizer turbopump was
9828_84	provided by a high-speed, two-stage turbine which was driven by the exhaust gases from the gas
9828_85	generator. The turbines of the oxidizer and fuel turbopumps were connected in a series by exhaust
9828_86	ducting that directed the discharged exhaust gas from the fuel turbopump turbine to the inlet of
9828_87	the oxidizer turbopump turbine manifold. One static and two dynamic seals in series prevented the
9828_88	turbopump oxidizer fluid and turbine gas from mixing.
9828_89	Beginning the turbopump operation, hot gas entered the nozzles and, in turn, the first stage
9828_90	turbine wheel. After passing through the first stage turbine wheel, the gas was redirected by the
9828_91	stator blades and entered the second stage turbine wheel. The gas then left the turbine through
9828_92	exhaust ducting, passed through the heat exchanger, and exhausted into the thrust chamber through a
9828_93	manifold directly above the fuel inlet manifold. Power from the turbine was transmitted by means of
9828_94	a one-piece shaft to the pump. The velocity of the LOX was increased through the inducer and
9828_95	impeller. As the LOX entered the outlet volute, velocity was converted to pressure and the LOX was
9828_96	discharged into the outlet duct at high pressure.
9828_97	Fuel and oxidizer flowmeters
9828_98	The fuel and oxidizer flowmeters were helical-vaned, rotor-type flowmeters. They were located in
9828_99	the fuel and oxidizer high-pressure ducts. The flowmeters measured propellant flowrates in the
9828_100	high-pressure propellant ducts. The four-vane rotor in the hydrogen system produced four electrical
9828_101	impulses per revolution and turned approximately 3,700 rpm at nominal flow. The six-vane rotor in
9828_102	the LOX system produced six electrical impulses per revolution and turned at approximately
9828_103	2,600 rpm at nominal flow.
9828_104	Valves
9828_105	The propellant feed system required a number of valves to control the operation of the engine by
9828_106	changing the flow of propellant through the engine's components:
9828_107	The main fuel valve was a butterfly-type valve, spring-loaded to the closed position, pneumatically
9828_108	operated to the open position, and pneumatically assisted to the closed position. It was mounted
9828_109	between the fuel high-pressure duct from the fuel turbopump and the fuel inlet manifold of the
9828_110	thrust chamber assembly. The main fuel valve controlled the flow of fuel to the thrust chamber.
9828_111	Pressure from the ignition stage control valve on the pneumatic control package opened the valve
9828_112	during engine start and, as the gate started to open, it allowed fuel to flow to the fuel inlet
9828_113	manifold.
9828_114	The main oxidizer valve (MOV) was a butterfly-type valve, spring-loaded to the closed position,
9828_115	pneumatically operated to the open position, and pneumatically assisted to the closed position. It
9828_116	was mounted between the oxidizer high-pressure duct from the oxidizer turbopump and the oxidizer
9828_117	inlet on the thrust chamber assembly. Pneumatic pressure from the normally closed port of the
9828_118	mainstage control solenoid valve was routed to both the first and second stage opening actuators of
9828_119	the main oxidizer valve. Application of opening pressure in this manner, together with controlled
9828_120	venting of the main oxidizer valve closing pressure through a thermal-compensating orifice,
9828_121	provided a controlled ramp opening of the main oxidizer valve through all temperature ranges. A
9828_122	sequence valve, located within the MOV assembly, supplied pneumatic pressure to the opening control
9828_123	part of the gas generator control valve and through an orifice to the closing part of the oxidizer
9828_124	turbine bypass valve.
9828_125	The propellant utilization (PU) valve was an electrically operated, two-phase, motor-driven,
9828_126	oxidizer transfer valve and is located at the oxidizer turbopump outlet volute. The propellant
9828_127	utilization valve ensured the simultaneous exhaustion of the contents of the propellant tanks.
9828_128	During engine operation, propellant level sensing devices in the vehicle propellant tanks
9828_129	controlled the valve gate position for adjusting the oxidizer flow to ensure simultaneous
9828_130	exhaustion of fuel and oxidizer.
9828_131	An additional function of the PU Valve was to provide thrust variations in order to maximize
9828_132	payload. The second stage, for example, operated with the PU valve in the closed position for more
9828_133	than 70% of the firing duration. This valve position provided of thrust at a 5.5:1 propellant
9828_134	(oxidizer to fuel by weight) mixture ratio (when the PU valve was fully open, the mixture ratio was
9828_135	4.5:1 and the thrust level was ), though with a higher specific impulse due to more unburned
9828_136	hydrogen in the exhaust. During the latter portion of the flight, the PU valve position was varied
9828_137	to provide simultaneous emptying of the propellant tanks. The third stage also operated at the
9828_138	high-thrust level for the majority of the burning time in order to realize the high thrust
9828_139	benefits. The exact period of time at which the engine operated with the PU valve closed varied
9828_140	with individual mission requirements and propellant tanking levels.
9828_141	The propellant bleed valves used in both the fuel and oxidizer systems were poppet-type, which were
9828_142	spring-loaded to the normally open position and pressure-actuated to the closed position. Both
9828_143	propellant bleed valves were mounted to the bootstrap lines adjacent to their respective turbopump
9828_144	discharge flanges. The valves allowed propellant to circulate in the propellant feed system lines
9828_145	to achieve proper operating temperature prior to engine start, and were engine controlled. At
9828_146	engine start, a helium control solenoid valve in the pneumatic control package was energized
9828_147	allowing pneumatic pressure to close the bleed valves, which remained closed during engine
9828_148	operation.
9828_149	Gas generator and exhaust system
9828_150	The gas generator system consisted of the gas generator, gas generator control valve, turbine
9828_151	exhaust system and exhaust manifold, heat exchanger, and oxidizer turbine bypass valve.
9828_152	Gas generator
9828_153	The gas generator itself was welded to the fuel pump turbine manifold, making it an integral part
9828_154	of the fuel turbopump assembly. It produced hot gases to drive the fuel and oxidizer turbines and
9828_155	consisted of a combustor containing two spark plugs, a control valve containing fuel and oxidizer
9828_156	ports, and an injector assembly. When engine start was initiated, the spark exciters in the
9828_157	electrical control package were energized, providing energy to the spark plugs in the gas generator
9828_158	combustor. Propellants flowed through the control valve to the injector assembly and into the
9828_159	combustor outlet, before being directed to the fuel turbine and then to the oxidizer turbine.
9828_160	Valves
9828_161	The gas generator control valve was a pneumatically operated poppet-type that was spring-loaded to
9828_162	the closed position. The fuel and oxidizer poppets were mechanically linked by an actuator. The
9828_163	valve controlled the flow of propellants through the gas generator injector. When the mainstage
9828_164	signal was received, pneumatic pressure was applied against the gas generator control valve
9828_165	actuator assembly which moved the piston and opened the fuel poppet. During the fuel poppet
9828_166	opening, an actuator contacted the piston that opened the oxidizer poppet. As the opening pneumatic
9828_167	pressure decayed, spring loads closed the poppets.
9828_168	The oxidizer turbine bypass valve was a normally open, spring-loaded, gate type valve. It was
9828_169	mounted in the oxidizer turbine bypass duct and equipped with a nozzle, the size of which was
9828_170	determined during engine calibration. The valve in its open position depressed the speed of the
9828_171	oxygen pump during start, and in its closed position acted as a calibration device for the
9828_172	turbopump performance balance.
9828_173	Turbine exhaust system

9828_74

wheel, the gas was redirected through a ring of stator blades and enters the second stage turbine

9828_75

wheel. The gas left the turbine through the exhaust ducting. Three dynamic seals in series

9828_76

prevented the pump fluid and turbine gas from mixing. Power from the turbine was transmitted to the

9828_77

pump by means of a one-piece shaft.

9828_78

Oxidizer turbopump

9828_79

The oxidizer turbopump was mounted on the thrust chamber diametrically opposite the fuel turbopump.

9828_80

It was a single-stage centrifugal pump with direct turbine drive. The oxidizer turbopump increases

9828_81

the pressure of the LOX and pumps it through high-pressure ducts to the thrust chamber. The pump

9828_82

operated at 8,600 rpm at a discharge pressure of (absolute) and developed . The pump and its two

9828_83

turbine wheels are mounted on a common shaft. Power for operating the oxidizer turbopump was

9828_84

provided by a high-speed, two-stage turbine which was driven by the exhaust gases from the gas

9828_85

generator. The turbines of the oxidizer and fuel turbopumps were connected in a series by exhaust

9828_86

ducting that directed the discharged exhaust gas from the fuel turbopump turbine to the inlet of

9828_87

the oxidizer turbopump turbine manifold. One static and two dynamic seals in series prevented the

9828_88

turbopump oxidizer fluid and turbine gas from mixing.

9828_89

Beginning the turbopump operation, hot gas entered the nozzles and, in turn, the first stage

9828_90

turbine wheel. After passing through the first stage turbine wheel, the gas was redirected by the

9828_91

stator blades and entered the second stage turbine wheel. The gas then left the turbine through

9828_92

exhaust ducting, passed through the heat exchanger, and exhausted into the thrust chamber through a

9828_93

manifold directly above the fuel inlet manifold. Power from the turbine was transmitted by means of

9828_94

a one-piece shaft to the pump. The velocity of the LOX was increased through the inducer and

9828_95

impeller. As the LOX entered the outlet volute, velocity was converted to pressure and the LOX was

9828_96

discharged into the outlet duct at high pressure.

9828_97

Fuel and oxidizer flowmeters

9828_98

The fuel and oxidizer flowmeters were helical-vaned, rotor-type flowmeters. They were located in

9828_99

the fuel and oxidizer high-pressure ducts. The flowmeters measured propellant flowrates in the

9828_100

high-pressure propellant ducts. The four-vane rotor in the hydrogen system produced four electrical

9828_101

impulses per revolution and turned approximately 3,700 rpm at nominal flow. The six-vane rotor in

9828_102

the LOX system produced six electrical impulses per revolution and turned at approximately

9828_103

2,600 rpm at nominal flow.

9828_104

Valves

9828_105

The propellant feed system required a number of valves to control the operation of the engine by

9828_106

changing the flow of propellant through the engine's components:

9828_107

The main fuel valve was a butterfly-type valve, spring-loaded to the closed position, pneumatically

9828_108

operated to the open position, and pneumatically assisted to the closed position. It was mounted

9828_109

between the fuel high-pressure duct from the fuel turbopump and the fuel inlet manifold of the

9828_110

thrust chamber assembly. The main fuel valve controlled the flow of fuel to the thrust chamber.

9828_111

Pressure from the ignition stage control valve on the pneumatic control package opened the valve

9828_112

during engine start and, as the gate started to open, it allowed fuel to flow to the fuel inlet

9828_113

manifold.

9828_114

The main oxidizer valve (MOV) was a butterfly-type valve, spring-loaded to the closed position,

9828_115

pneumatically operated to the open position, and pneumatically assisted to the closed position. It

9828_116

was mounted between the oxidizer high-pressure duct from the oxidizer turbopump and the oxidizer

9828_117

inlet on the thrust chamber assembly. Pneumatic pressure from the normally closed port of the

9828_118

mainstage control solenoid valve was routed to both the first and second stage opening actuators of

9828_119

the main oxidizer valve. Application of opening pressure in this manner, together with controlled

9828_120

venting of the main oxidizer valve closing pressure through a thermal-compensating orifice,

9828_121

provided a controlled ramp opening of the main oxidizer valve through all temperature ranges. A

9828_122

sequence valve, located within the MOV assembly, supplied pneumatic pressure to the opening control

9828_123

part of the gas generator control valve and through an orifice to the closing part of the oxidizer

9828_124

turbine bypass valve.

9828_125

The propellant utilization (PU) valve was an electrically operated, two-phase, motor-driven,

9828_126

oxidizer transfer valve and is located at the oxidizer turbopump outlet volute. The propellant

9828_127

utilization valve ensured the simultaneous exhaustion of the contents of the propellant tanks.

9828_128

During engine operation, propellant level sensing devices in the vehicle propellant tanks

9828_129

controlled the valve gate position for adjusting the oxidizer flow to ensure simultaneous

9828_130

exhaustion of fuel and oxidizer.

9828_131

An additional function of the PU Valve was to provide thrust variations in order to maximize

9828_132

payload. The second stage, for example, operated with the PU valve in the closed position for more

9828_133

than 70% of the firing duration. This valve position provided of thrust at a 5.5:1 propellant

9828_134

(oxidizer to fuel by weight) mixture ratio (when the PU valve was fully open, the mixture ratio was

9828_135

4.5:1 and the thrust level was ), though with a higher specific impulse due to more unburned

9828_136

hydrogen in the exhaust. During the latter portion of the flight, the PU valve position was varied

9828_137

to provide simultaneous emptying of the propellant tanks. The third stage also operated at the

9828_138

high-thrust level for the majority of the burning time in order to realize the high thrust

9828_139

benefits. The exact period of time at which the engine operated with the PU valve closed varied

9828_140

with individual mission requirements and propellant tanking levels.

9828_141

The propellant bleed valves used in both the fuel and oxidizer systems were poppet-type, which were

9828_142

spring-loaded to the normally open position and pressure-actuated to the closed position. Both

9828_143

propellant bleed valves were mounted to the bootstrap lines adjacent to their respective turbopump

9828_144

discharge flanges. The valves allowed propellant to circulate in the propellant feed system lines

9828_145

to achieve proper operating temperature prior to engine start, and were engine controlled. At

9828_146

engine start, a helium control solenoid valve in the pneumatic control package was energized

9828_147

allowing pneumatic pressure to close the bleed valves, which remained closed during engine

9828_148

operation.

9828_149

Gas generator and exhaust system

9828_150

The gas generator system consisted of the gas generator, gas generator control valve, turbine

9828_151

exhaust system and exhaust manifold, heat exchanger, and oxidizer turbine bypass valve.

9828_152

Gas generator

9828_153

The gas generator itself was welded to the fuel pump turbine manifold, making it an integral part

9828_154

of the fuel turbopump assembly. It produced hot gases to drive the fuel and oxidizer turbines and

9828_155

consisted of a combustor containing two spark plugs, a control valve containing fuel and oxidizer

9828_156

ports, and an injector assembly. When engine start was initiated, the spark exciters in the

9828_157

electrical control package were energized, providing energy to the spark plugs in the gas generator

9828_158

combustor. Propellants flowed through the control valve to the injector assembly and into the

9828_159

combustor outlet, before being directed to the fuel turbine and then to the oxidizer turbine.

9828_160

Valves

9828_161

The gas generator control valve was a pneumatically operated poppet-type that was spring-loaded to

9828_162

the closed position. The fuel and oxidizer poppets were mechanically linked by an actuator. The

9828_163

valve controlled the flow of propellants through the gas generator injector. When the mainstage

9828_164

signal was received, pneumatic pressure was applied against the gas generator control valve

9828_165

actuator assembly which moved the piston and opened the fuel poppet. During the fuel poppet

9828_166

opening, an actuator contacted the piston that opened the oxidizer poppet. As the opening pneumatic

9828_167

pressure decayed, spring loads closed the poppets.

9828_168

The oxidizer turbine bypass valve was a normally open, spring-loaded, gate type valve. It was

9828_169

mounted in the oxidizer turbine bypass duct and equipped with a nozzle, the size of which was

9828_170

determined during engine calibration. The valve in its open position depressed the speed of the

9828_171

oxygen pump during start, and in its closed position acted as a calibration device for the

9828_172

turbopump performance balance.

9828_173

Turbine exhaust system