Abstract: A sheet metal electrode for forming a shaped, diffusing film coolant passage has a straight, longitudinally extending forward section forming an acute angle with a flat middle section, which, in turn, extends from a rear section which is the base of the electrode. The middle section includes a pair of edges rearwardly diverging from the longitudinal direction and from which extend side walls substantially perpendicular to the middle section. Longitudinally extending edges of the side walls are in the same plane as a lower, flat surface of the forward section such that the surface of the passage formed by such lower surface of the forward section is in the same plane as a surface of the diffusing portion of the passage which is formed by the longitudinally extending edges of the side walls.

Abstract: A stage of circumferentially disposed turbine stator vane clusters and arcuate, circumferentially disposed segments of a rotor outer air seal disposed on one side of the stator stage is secured to an annular attachment ring which is integral with a surrounding turbine case. The outer seal segments are trapped axially between stator vane clusters and the radially inner ends of arcuate support segments, and are also radially supported thereby. The radially inner ends of the support segments are trapped axially between the stator vane clusters and the annular attachment ring, and are also supported radially thereby. This boltless attachment reduces the number of parts while providing strong radially support and accurate radial location for the seal segments.

Abstract: Electrolyte is replenished in a fully assembled stack of fuel cells by depositing dilute electrolyte of known concentration on an external vertical face of the stack. The electrolyte is absorbed into the cell components through their edges by capillary action. Electrolyte is continuously deposited on the stack surface until the electrodes and matrix layers of the stack are fully saturated. Thereafter the stack is heated and water is evaporated until the stack has a desired operable electrolyte volume and electrolyte concentration therein. By knowing the total volume of electrolyte in the stack when the stack is fully saturated, and by knowing the concentration of the electrolyte in the fully saturated stack, the conditions under which water is thereafter evaporated may be controlled to result in the desired electrolyte volume and electrolyte concentration within the stack.

Abstract: An engine nozzle construction having a flap nozzle at the end of an engine exhaust duct, said flap nozzle variably controlling exhaust flow providing a primary flow path, said flap nozzle being movable to a position to direct the exhaust flow from said exhaust duct into a peripheral chamber, said chamber having exit openings around it providing for a secondary flow path for the exhaust flow.

Abstract: A turbine airfoil for high temperature applications has a spanwise trailing edge slot and a cut back pressure side wall. The pressure side wall has a thickness t at its downstream end. The slot is divided into channels which discharge a film of cooling air over the exposed back surface of the suction side wall downstream of the cut back pressure side wall. Each channel tapers from a throat at its upstream end (which meters the flow of cooling air) to the slot outlet of width s. The airfoil is designed with a ratio t/s of no more than 0.7 which significantly improves cooling of the trailing edge, reduces required cooling air flow, and permits greater cut back distances.

Abstract: Electrolyte is replenished in a fully assembled stack of fuel cells by depositing dilute electrolyte on tabs extending outwardly from an external vertical face of the stack. The electrolyte is absorbed into the cell components as it cascades off the tabs and down the face of the stack. When the electrodes and matrix layers of the stack are fully saturated the stack is heated and water is evaporated until the stack has an operable electrolyte volume and electrolyte concentration therein. In a preferred embodiment the tabs are extensions of the nonporous plates separating adjacent cells in the stack.

Abstract: Electrolyte lost from a fuel cell, such as by evaporation, is replenished by introducing electrolyte from an external source into a reactant gas stream being delivered into the cell. The fresh electrolyte is vaporized or formed into droplets as it enters the cell such as by spraying the fresh electrolyte into the gas stream. If the electrolyte vapor pressure in the entering gas stream is made high enough, evaporation of the electrolyte from the cell can be halted or electrolyte can even be added to the cell from the gas stream.

Abstract: A control system for a twin spool gas turbine engine for synthesizing a control parameter for the engine (such as the ratio of high compressor inlet temperature to low compressor inlet temperature) includes a function generator responsive to an engine operating parameter (such as corrected rotor speed) to generate a simulated value of the control parameter for a base engine configuration. A second function generator, responsive to an engine operating parameter, generates a simulated value of the difference between the value of the control parameter for the base engine configuration and the value of the parameter for another configuration. This difference is operated upon to correct it to the actual engine configuration. The corrected difference is added to the simulated value of the control parameter for the base configuration to give a simulated value of the control parameter for the actual engine configuration.

Abstract: A two-dimensional variable area convergent/divergent exhaust nozzle having the capability for wide throat area variation includes upper and lower spaced apart flap means. The upper flap means comprises an upstream converging flap having its rear edge hinged to the forward edge of a downstream diverging flap, wherein the nozzle is movable between maximum and minimum throat area positions by actuation means which includes guide means, such as cam tracks, for guiding the forward edge of the upstream flap to move downstream while simultaneously constraining both the upper flap means hinge joint and the rear edge of the diverging flap to move both downstream and closer to the engine axis. This type of motion permits large changes in throat area with minimal increase in the slope of the diverging flap permitting use of a shorter diverging flap. Preferably the forward and rearward edge of the converging flap move along circular arcs having the same center in order to minimize moments on the flap.

Abstract: A spacer extends between and engages the rear face of a first disk and front face of a second disk of co-rotating rotors of a two stage turbine. The spacer engages the disks radially inwardly of the blade root slots of each disk and defines an intermediate cooling air compartment between the disks, radially inward of the spacer. Each disk includes blade root slots, each having a blade root disposed therein and defining a cooling air passageway across each slot from the front to rear face of each disk. Cooling air from a compartment upstream of the first disk is directed downstream through the passageways across the slots and thence radially inwardly into the intermediate compartment between the disks. From the intermediate compartment the cooling air travels radially outwardly and then axially through the cooling air passageways across the second disk blade root slots.

Abstract: Nonrecoverable compressor rotating stall in a gas turbine engine is detected virtually at its onset by continuously calculating corrected engine speed and measuring the compressor pressure ratio. Associated with each corrected engine speed is a predetermined, empirically calculated critical pressure ratio. When the actual pressure ratio equals or falls below the critical pressure ratio a nonrecoverable stall has been detected and an output signal is generated which warns the pilot or automatically causes corrective action to be taken.

Abstract: A seal plate rests along the edge of a moveable flap surface and extends outwardly therefrom into contact with a stationary wall to seal the gap between the flap edge and the wall. The seal plate is hinged for rotation to one end of a pivotable support link which is hinged at its other end to the flap. The gas pressure load on the seal plate presses it against the flap surface and also tends to rotate the support link to press the outward edge of the seal plate against the stationary wall.

Abstract: A blade vibration damper for a rotor assembly of an axial flow machine seats simultaneously on a radially inwardly facing surface of a blade platform and the radially inwardly facing surface of an adjacent element, such as the platform of a circumferentially adjacent blade. The damper has its mass center of gravity nearer one contact area than the other so as to reduce the normal load on the blade platform generated by centrifugal force. By properly locating the center of gravity of the damper, the size of the normal force can be optimized to maximize damping.

Abstract: A device for securing an annular blade retaining plate to a rotor disk includes an annular groove around the disk for receiving an off-set annular flange on the inner end of said blade retaining plate. A split retainer ring extends from a second groove intersecting said first groove to fix the blade retainer ring to the disk. A locking ring is positioned between said split retainer ring and said blade retaining plate to maintain said split retainer ring in its groove.

Abstract: Divergent flaps of an axisymmetric exhaust nozzle include a hot inner gas path wall spaced from an outer wall to define a cooling fluid channel therebetween along the length of the flap from the upstream end of the flap near the divergent nozzle throat to near the downstream end of the flap. A slot or other opening in the flap inner wall at or just downstream of the nozzle throat communicates with the upstream end of the channel. Openings in the flap outer wall near the downstream end of the flap provide communication between the channel and external ambient air at a higher pressure than the gas at the nozzle throat. Ambient air thus travels upstream through the channel, convectively cooling the hot inner wall and exits through the slot in the inner wall at or near the throat to film cool the gas path side of the inner wall.

Abstract: In a hollow airfoil, thin metal baffle sheets are bonded to opposing suction and pressure sides of a longitudinally extending cooling air cavity. The longitudinally extending downstream edges of these opposing baffle sheets are closely spaced apart defining a cooling air outlet slot for the cavity which may, for example, feed cooling air to the trailing edge portion of the airfoil. If the rearward edges of either baffle sheet become unbonded from the inside cavity wall the edge of the baffle sheet might bend inwardly and close the outlet slot. To prevent this possibility a plurality of pedestals extend outwardly from each side of the cavity wall opposite the rearward edge of each baffle sheet and extending substantially to the inwardly facing surface of that baffle sheet trapping it against the wall.

Abstract: The steam for a steam reforming reactor of a fuel cell powerplant is generated by humidifying the reactor feed gas in a saturator by evaporating a small portion of a mass of liquid water which circulates in a loop passing through the saturator. The water is reheated in each pass through the loop by waste heat from the fuel cell, but is not boiled. In the saturator the relatively dry feed gas passes in direct contact with the liquid water over and through a bed a high surface area material to cause evaporation of some of the water in the loop. All the steam requirements for the reactor can be generated in this manner without the need for a boiler; and steam can be raised at a higher total pressure than in a boiler heated by the same source.

Abstract: Stress relief for the rim of an integrally bladed rotor made from a forging preform is provided by forming a plurality of radially extending circumferentially spaced-apart slots around the periphery of the preform. The slots are forged closed in a subsequent forming step. An oxide layer on the slot surfaces prevents the surfaces from bonding together when forged closed. The blades are formed between slots during the forging or by machining after forging.

Abstract: Electrolyte vapor entrained in the hot exhaust gas stream from a fuel cell is removed by passing the gas stream through a saturator, over high surface area material, in direct contact with water circulating in a loop which also passes through the saturator. The hot gas stream evaporates a small portion of the water, resulting in cooling of the gas stream and condensing of electrolyte therein as it cools. The electrolyte dissolves into the recirculating water. The water is exchanged at predetermined intervals or when the concentration of electrolyte reaches a predetermined level. At least 99% of the electrolyte can be removed from the gas stream in this manner.

Abstract: A die package for forming a central disc structure having a plurality of integrally formed appendages extending therefrom includes a cylindrical array of appendage forming, abutting die segments which are prevented from tilting or moving in a circumferential direction by means of pins extending into slots formed along the parting lines between abutting die segments in the upper surfaces of the segments. In one embodiment, the pins extend upwardly from between opposed, parallel, radially and axially extending walls of each slot and fit tightly between said walls. The upper ends of the pins are secured to a rigid annular ring overlying the slots. The slots extend radially inwardly of the pins to allow the die segments to be moved radially outwardly after forging to release the forging from the die package.