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The use of centrifugal pumps for rocket engines is described in terms of general requirements of operational and planned systems. Hydrodynamic and mechanical design considerations and techniques and test procedures are summarized. Some of the pump development experiences, in terms of both problems and solutions, are highlighted.
The characteristics of a rocket pump inducer are discussed. The effect of the pumping requirements on the blade configuration is analyzed. The effects of viscosity on blade design were determined by tests of a four bladed inducer operated in air at a flow coefficient of 0.065. The fluid properties were measured at the exit of the inducer using conventional and hot wire probes. The experimental results and the method of predicting the outlet tangential velocity and head rise are discussed.
A two-phase mathematical model is proposed for calculating the induced turbulent vertical liquid flow. Bubbles provide a large buoyancy force and the associated drag on the liquid moves the liquid upward. The liquid pumped upward consists of the bubble wakes and the liquid brought into the jet region by turbulent entrainment. The expansion of the gas bubbles as they rise through the liquid is taken into account. The continuity and momentum equations are solved numerically for an axisymmetric air jet submerged in water. Water pumping rates are obtained as a function of air flow rate and depth of submergence. Comparisons are made with limited experimental information in the literature.
Special considerations to be given to the design, fabrication, and use of centrifugal pumps for liquid O2 to avoid conditions that lead to system failure are given. Emphasis was placed on turbine pumps for flight applications.
From observations of a stream of gas bubbles rising through a liquid, a two-phase mathematical model is proposed for calculating the induced turbulent vertical liquid flow. The bubbles provide a large buoyancy force and the associated drag on the liquid moves the liquid upward. The liquid pumped upward consists of the bubble wakes and the liquid brought into the jet region by turbulent entrainment. The expansion of the gas bubbles as they arise through the liquid is taken into account. The continuity and momentum equations are solved numerically for an axisymmetric air jet submerged in water. Water pumping rates are obtained as a function of air flow rate and depth of submergence. Comparisons are made with limited experimental information in the literature.
The new nonmagnetic ion pump resembles the quadrupole ionization gage. The dimensions are larger, and hyperbolically shaped electrodes replace the four rods. Their surfaces follow y sq. = 36 + x sq. (x, y in centimeters). The electrodes, 55 cm long, are positioned lengthwise in a tube. At one end a cathode emits electrons; at the other end a narrowly wound flat spiral of tungsten clad with titanium on cathode potential can be heated for titanium evaporation. Electrons accelerated by a dc potential of the surface electrodes oscillate between the ends on rotational trajectories, if a high frequency potential superimposed on the dc potential is properly adjusted. Pumping speeds (4-100 liter/sec) for different gases at different peak voltages (1000-3000V) at corresponding frequencies (57-100 MHz), and at different pressures 0.00001 to the minus 9 power Torr were observed. The lowest pressure reached was below 10 to the minus 10 power Torr.
A solar powered pump particularly suited for intermittently delivering a stream of water is reported. The pump is characterized by a housing adapted to be seated in a source of water having a water discharge port disposed above the water line of the source, a sump including a valved inlet port through which water is introduced to the sump, disposed beneath the water line, a displacer supported for vertical reciprocation in said housing, an air passageway extended between the vertically spaced faces of the displacer, and a tipple disposed adjacent to the water discharge port adapted to be filled in response to a discharge of water from the housing. Air above a displacer is expanded in response to solar energy impinging on the housing and transferred into pressurizing relation with the sump for forcing water from the sump.
It is shown that magnetic heat pumping can be made practical at room temperature by using a ferromagnetic material with a Curie point at or near operating temperature and an appropriate regenerative thermodynamic cycle. Measurements are performed which show that gadolinium is a resonable working material and it is found that the application of a 7-T magnetic field to gadolinium at the Curie point (293 K) causes a heat release of 4 kJ/kg under isothermal conditions or a temperature rise of 14 K under adiabatic conditions. A regeneration technique can be used to lift the load of the lattice and electronic heat capacities off the magnetic system in order to span a reasonable temperature difference and to pump as much entropy per cycle as possible
The considered asymptotic relationship is investigated and an expression is sought for the slope of the curve representing the relation between the residual fractional transmitted pump and the pump excitation in backward-traveling-wave amplification. It is found that the characteristic -2 slope of the oscillation curve is a unique property. Rapid exponential decay may very well constitute an inherent limiting factor for efficient energy conversion.
The letter reports direct nuclear pumping of (He-3)-Xe and (He-3)-Kr using the volumetric He-3(n,p)H-3 nuclear reaction. Lasing in (He-3)-Xe was achieved at the 2.027-micron transition of Xe I; lasing in (He-3)-Kr is assumed to have occurred at the 2.52-micron transition of Kr I. Experimental results show that laser output in (He-3)-Xe increases and tends to saturate with increasing pressure, the lasing neutron-flux threshold decreases with decreasing neutron pulse, and maximum output occurs between 0.1% and 0.5% Xe with the total pressure held constant at 400 torr and with an average neutron flux of 6 by 10 to the 15th power per sq cm/sec. It is noted that the (He-3)-Xe laser has the lowest lasing-threshold neutron flux of any He-3 nuclear-pumped laser to date, but the (He-3)-Kr laser has a very high threshold flux. The primary lasing mechanism is believed to be Penning ionization of Xe and Kr followed by collisional radiative recombination and cascading into the upper laser level.
An optically pumped regenerative submillimeter laser amplifier is described. The amplifier uses a waveguide cavity resonator, and a Fabry-Perot interferometer composed of two dielectric-coated mirrors serves as input and output port for the submillimeter signal. Use of two mirrors enabled obtaining variations of up to 6:1 in transmission by varying the mirror spacing. When the 373-micron transition in CH3CN is excited in the oscillator by the CO2 laser pump beam, the received signal with amplification is about nine times the unamplified signal.
Quantum mechanical predictions for the gain of an optically pumped CW FIR laser are presented for cases in which one or both of the pump and FIR transitions are pressure or Doppler broadened. The results are compared to those based on the rate equation model. Some of the quantum mechanical predictions are verified in CH3OH.
Operating experience in pumping coal and coal char slurries at pressures up to 1500 psig is discussed. The design specifications for the mixing tanks, pumps, piping, and slurry heaters are given along with pressure drop and minimum flow velocity data on water-lignite slurries.
Water pumping applications represent a potential market for photovoltaics. The price of energy for photovoltaic systems was compared to that of utility line extensions and diesel generators. The potential domestic demand was defined in the government, commercial/institutional and public sectors. The foreign demand and sources of funding for water pumping systems in the developing countries were also discussed briefly. It was concluded that a near term domestic market of at least 240 megawatts and a foreign market of about 6 gigawatts exist.
A solar-operated pump using an existing solar collector, for use on solar heating and cooling and hot water systems is described. Preliminary design criteria of the collector and solar-powered pump is given including: design drawings, verification plans, and hazard analysis.
The construction and method of working of a helium adsorption pump are described. The flux of helium-2 film can be suppressed by an appropriate construction, which permits it to reach temperatures down to 0.71 K. By total utilization of the pump's cross-section, temperatures from 1.2 K to 0.71 K remain constant for several hours with a precision of 0.001 K.
In order to determine the physical processes for pumping this laser, a detailed study of the afterglow system has been performed. The pumping mechanism has been found to be collisional-radiative electron-ion recombination. Microwave quenching of both the laser and spontaneous afterglow light have shown conclusively that a recombination process directly produces a nitrogen atom in either the upper laser level or, more likely, in a higher lying energy level which rapidly de-excites to the upper laser level.
The laser energy at optimum time delay of a double-pulsed CuCl laser was experimentally determined to be a logarithmic function of the initial current rise of the pumping pulse over the total circuit inductance range 1 to 12 microhenrys. The minimum delay was found to decrease with initial current rise, which implies that faster rising current pulses are more efficient at pumping copper atoms from the ground state to the upper laser level because lasing threshold occurs with a higher population in the lower laser level.