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Bellows configurations design, pressure loss, and vibration tests to minimize pressure drop and improve gas and liquid flow in spacecraft high velocity duct systems
Compressible and incompressible flow calculations were made of the combustor total-pressure-loss coefficient and liner airflow distribution for tubular turbojet combustors having constant annulus and liner cross-sectional areas along the combustor axis. Information on static and total pressure distribution and liner air-jet entrance angles along the length of the combustor was obtained as an intermediate step in the calculations. The calculations include the effects of heat release, annulus wall friction, and variation in discharge coefficients of the liner wall openings along the combustor. The combustor total-pressure-loss coefficient and liner air-flow distribution are presented graphically in terms of the following dimensionless parameters: (1) combustor reference Mach number, (2) ratio of combustor-exit to inlet total temperature, (3) fraction of total airflow passing through the liner dome, (4) ratio of total open hole area in liner wall to total combustor cross-sectional area, and (5) ratio of liner cross-sectional area to total combustor cross-sectional area.
Abstract Additive manufacturing (AM) provides the ability to fabricate highly customized internal cooling passages that are relevant to gas turbine components. This experimental study examines the pressure loss and heat transfer performance of a range of fundamental channel shapes that were produced using direct metal laser sintering. Circular, hexagonal, pentagonal, elliptical, diamond, square, rectangular, trapezoidal, and triangular channel cross sections were investigated. To maintain the same convective surface area between shapes, the wetted perimeters of the channel cross sections were kept constant. Parallel computational fluid dynamic simulations were performed to understand the relationships in cooling performance between several channel shapes. Several characteristic length scales were evaluated to scale the pressure loss and heat transfer measurements. Among the channel shapes investigated, the diamond channel showed the lowest Nusselt number and friction factor. The pentagon exhibited a similar Nusselt number as the circular channel despite having a lower friction factor. There was no difference in scaling the friction factor or Nusselt number results of the different channel shapes between using the square root of cross-sectional area compared to hydraulic diameter as the characteristic length scale
Low-pressure-loss short afterburner design for sea level thrust augmentation of axial flow turbojet engine
Pressure losses in tubing and fittings - flow systems analysis, entrance effects in flexible metal hoses, and methods for analyzing flow over rough surface
Classical and zero-total pressure-loss sets of Euler equations were applied to sharp- and round-edge delta wings. The origin of the total pressure was explained in the classical set. For sharp-edged delta wings, all sets of Euler equations produce the same separated flow solutions. For round-edged delta wings and for coarse grids, the solution depends on the level of dissipation, the accuracy of the surface boundary condition, and the type of Euler equations set. For round-edged delta wings and for fine grids, attached flow solutions are obtained. Also presented were three dimensional flow solutions and asymmetric flow solutions including unsteady flow for sharp-edged delta wings. Euler equations should be restricted to sharp-edged wings for real flow solutions. For roung-edged wings, Navier-Stokes equations must be used.
Computer analysis of total pressure loss and air flow distribution in annular flow gas turbine combustion chambers
An effort is made to quantify the stagnation pressure losses associated with shock-wave systems that may be present in such high Mach number flows as those of scramjet hypersonic diffusers. If the shock-related contribution turns out to be much larger than that attributable to viscous effects, a designer could introduce methods for the minimization of the shock system's scale; in particular, the size of the normal shock should be reduced. The angles presently treated may be approached during vehicle maneuvering or other transients.
Performance characteristics at simulated high altitudes of prevaporizing annular turbojet combustor with low pressure loss
Study of ducting and duct components to minimize pressure loss in space vehicle high velocity feed system
Theoretical analysis and measurement of single-phase pressure losses and heat transfer for helical flow in tube
The velocity profiles upon which the pressure-loss calculations are based, are recomputed using the previously described method of reference (1960). The pressure drop is then computed using the energy integral equation; both rectangular and equilateral triangular ducts are considered. It is demonstrated that, using this equation, the pressure-drop parameter can be improved.
Total-pressure-loss coefficients, flow discharge coefficients, and friction factors were determined experimentally for the various area and geometry changes and flow passages within an air-cooled turbine vane. The results are compared with those of others obtained on similar configurations, both actual and large models, of vane passages. The supply and exit air pressures were controlled and varied. The investigation was conducted with essentially ambient-temperature air and without external flow of air over the vane.
Air-water flow pressure loss and phase distribution in tube with wire coil swirl generators
Theoretical investigations have shown that, because air is compressible, the pressure-drop requirements for cooling an air-cooled engine will be much greater at high altitudes and high speeds than at sea level and low speeds. Tests were conducted by the NACA to obtain some experimental confirmation of the effect of air compressibility on cooling and pressure loss of a baffled cylinder barrel and to evaluate various methods of analysis. The results reported in the present paper are regarded as preliminary to tests on single-cylinder and multicylinder engines. Tests were conducted over a wide range of air flows and density altitudes.
Theoretical investigations have shown that, because air is compressible, the pressure-drop requirements for cooling an air-cooled engine will be much greater at high altitudes and high speeds than at sea level and low speeds. Tests were conducted by the NACA to obtain some experimental confirmation of the effect of air compressibility on cooling and pressure loss of a baffled cylinder barrel and to evaluate various methods of analysis. The results reported in the present paper are regarded as preliminary to tests on single-cylinder and multi-cylinder engines. Tests were conducted over a wide range of air flows and density altitudes.
Smith correlation of turbine stage efficiency for relating achievable efficiency to stage loading and flow factors used for total pressure loss coefficient data
At the request of the Bureau of Aeronautics, Navy Department, investigations of the static-pressure losses and total-head distributions of the Westinghouse X24-C-2 inlet screen were made in the induction aerodynamics laboratory at Langley. The screen was investigated in two configurations, both before and after rounding the leading edges of the vanes. Investigations were conducted through air flows up to about pounds per second. The results of the investigations indicate that maximum lift coefficients of 1.36, 1.71 and 2.11 were measured on the model with flaps neutral and deflected 20 deg. and 55 deg, respectively, at a reynolds number of 8,600,000. When the duct inlet was replaced by a basic airfoil nose the flap neutral maximum lift coefficient was increased from 1.36 to 1.41. The results also showed that at maximum lift with flaps neutral or deflected 55 deg most of the area between the nacelles was stalled while only small areas on other portions of the model were stalled; when the duct inlet was replaced by the basic airfoil nose the stall was delayed to a slightly higher angle of attack but the nature of the stall was relatively unaffected.