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Results for “pressure loss”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1958

Theoretical analysis of total-pressure loss and airflow distribution for tubular turbojet combustors with constant annulus and liner cross-sectional areas

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.

Graves, Charles C↗
NASA NTRS1987

Applications of classical and zero-total-pressure-loss sets of Euler equations to delta wings

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.

Kandil, Osama A.↗
NASA NTRS1990

Prediction of inviscid stagnation pressure losses in supersonic inlet flows

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.

Azevedo, David J.↗
NASA NTRS1971

Pressure losses for laminar flow in the entrance region of ducts of rectangular and equilateral triangular cross section.

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.

Miller, R. W.↗
NASA NTRS1974

Pressure-loss and flow coefficients inside a chordwise-finned, impingement, convection, and film air-cooled turbine vane

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.

Hippensteele, S. A.↗
NASA NTRS1944

Compressibility and Heating Effects on Pressure Loss and Cooling of a Baffled Cylinder Barrel

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.

Goldstein, Arthur W↗
NASA NTRS1944

Compressibility and Heating Effects on Pressure Loss and Cooling of a Baffled Cylinder Barrel

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.

Goldstein, Arthur W.↗
NASA NTRS1946

Investigation of the Pressure-Loss Characteristics of the Westinghouse X24-C-2 Inlet Screen, TED No. NACA 0447

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.

Lankford, John L.↗
NASA NTRS1990

Turbulence and pressure loss characteristics of the inlet vanes for the 80- by 120-ft wind tunnel

A series of wind tunnel investigations were conducted to determine the flow characteristics downstream of a set of wind tunnel inlet flow conditioning vanes. The purpose was to develop an understanding of the flow mechanisms that contributed to the pressure loss and turbulence generated by the vane set. The near-field characteristics and flow field development were investigated with a 1/3 scale two dimensional model of the vane set at near full-scale Reynolds numbers. In a second series of tests, the global flow field characteristics were investigated by means of a 1/15 scale model of the full vane set and the 5:1 contraction leading to the model's test section. Scale effects due to Reynolds number mismatch were identified and their significance noted and accounted for when possible. Scaling parameters were adopted that allowed predictions to be made of the expected turbulence and pressure distributions in the full-scale wind tunnel test section, based on the small-scale test results. The predictions were found to be in good agreement with actual measurements made in the full-scale facility.

Dudley, Michael R.↗
NASA NTRS1988

Slender wing theory including regions of embedded total pressure loss

An aerodynamic theory of the flow about slender delta wings is described. The theory includes a treatment of the self-consistent development of the vortex wake patterns above the wing necessary to maintain smooth flow at the wing edges. The paper focuses especially on the formation within the wake of vortex 'cores' as embedded regions of total pressure loss, fed and maintained by umbilical vortex sheets emanating from the wing edges. Criteria are developed for determining the growing size and location of these cores, as well as the distribution and strength of the vorticity within them. In this paper, however, the possibility of vortex breakup is omitted. The aerodynamic consequences of the presence and evolution of the cores and the associated wake structure are illustrated and discussed. It is noted that wake history effects can have substantial influence on the distribution of normal force on the wing as well as on its magnitude.

Mccune, James E.↗