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Results for “separation force”

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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Computer-aided analysis and design of the shape rolling process for producing turbine engine airfoils

Mild steel (AISI 1018) was selected as model cold rolling material and Ti-6A1-4V and Inconel 718 were selected as typical hot rolling and cold rolling alloys, respectively. The flow stress and workability of these alloys were characterized and friction factor at the roll/workpiece interface was determined at their respective working conditions by conducting ring tests. Computer-aided mathematical models for predicting metal flow and stresses, and for simulating the shape rolling process were developed. These models utilized the upper bound and the slab methods of analysis, and were capable of predicting the lateral spread, roll separating force, roll torque, and local stresses, strains and strain rates. This computer-aided design system was also capable of simulating the actual rolling process, and thereby designing the roll pass schedule in rolling of an airfoil or a similar shape.

Lahoti, G. D.↗
NASA NTRS1978

Computer-aided analysis and design of the shape rolling process for producing turbine engine airfoils

Mild steel (AISI 1018) was selected as model cold-rolling material and Ti-6Al-4V and INCONEL 718 were selected as typical hot-rolling and cold-rolling alloys, respectively. The flow stress and workability of these alloys were characterized and friction factor at the roll/workpiece interface was determined at their respective working conditions by conducting ring tests. Computer-aided mathematical models for predicting metal flow and stresses, and for simulating the shape-rolling process were developed. These models utilize the upper-bound and the slab methods of analysis, and are capable of predicting the lateral spread, roll-separating force, roll torque and local stresses, strains and strain rates. This computer-aided design (CAD) system is also capable of simulating the actual rolling process and thereby designing roll-pass schedule in rolling of an airfoil or similar shape. The predictions from the CAD system were verified with respect to cold rolling of mild steel plates. The system is being applied to cold and hot isothermal rolling of an airfoil shape, and will be verified with respect to laboratory experiments under controlled conditions.

Lahoti, G. D.↗
NASA NTRS1979

Performance of end-face seals with diametral tilt and coning - Hydrodynamic effects

Hydrodynamic effects in end-face seals with diametral tilt and coning are analyzed. A closed-form solution for the axial separating force and the restoring and transverse moments is presented that covers the whole range from zero to full angular misalignment at various degrees of coning. Both low-pressure seals with cavitating flow and high-pressure seals with full fluid film are considered. The effect of coning is to reduce the axial force and the restoring and transverse moments compared to their magnitude in flat-face seals. Strong coupling between diametral tilt and transverse moment is demonstrated. This transverse moment which is entirely due to hydrodynamic effects can be the source of dynamic instability in the form of seal wobble.

Sharoni, A.↗
NASA NTRS1980

Computer-aided roll pass design in rolling of airfoil shapes

This paper describes two computer-aided design (CAD) programs developed for modeling the shape rolling process for airfoil sections. The first program, SHPROL, uses a modular upper-bound method of analysis and predicts the lateral spread, elongation, and roll torque. The second program, ROLPAS, predicts the stresses, roll separating force, the roll torque and the details of metal flow by simulating the rolling process, using the slab method of analysis. ROLPAS is an interactive program; it offers graphic display capabilities and allows the user to interact with the computer via a keyboard, CRT, and a light pen. The accuracy of the computerized models was evaluated by (a) rolling a selected airfoil shape at room temperature from 1018 steel and isothermally at high temperature from Ti-6Al-4V, and (b) comparing the experimental results with computer predictions. The comparisons indicated that the CAD systems, described here, are useful for practical engineering purposes and can be utilized in roll pass design and analysis for airfoil and similar shapes.

Akgerman, N.↗
NASA NTRS1994

Displaceable spur gear torque controlled driver and method

Methods and apparatus are provided for a torque driver including a laterally displaceable gear support member to carry an output spur gear. A biasing assembly biases the output spur gear into engagement with a pinion to which is applied an input torque greater than a desired output torque limit for a threaded fastener such as a nut or screw. A coiled output linkage connects the output spur gear with a fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. A gauged selector mechanism is provided to laterally displace multiple driver members for fasteners arranged in differing configurations. The torque limit is selectably adjustable and may be different for fasteners within the same fastener configuration.

Cook, Joseph S., Jr.↗
NASA NTRS1994

Pressurized fluid torque driver control and method

Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

Cook, Joseph S., Jr.↗
NASA NTRS1997

Displaceable Gear Torque Controlled Driver

Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

Cook, Joseph S., Jr.↗
NASA NTRS1996

Displaceable Spur Gear Torque Controlled Driver and Method

Methods and apparatus are provided for a torque driver including a laterally displaceable gear support member to carry an output spur gear. A biasing assembly biases the output spur gear into engagement with a pinion to which is applied an input torque greater than a desired output torque limit for a threaded fastener such as a nut or screw. A coiled output linkage connects the output spur gear with a fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. A gauged selector mechanism is provided to laterally displace multiple driven members for fasteners arranged in differing configurations. The torque limit is selectably adjustable and may be different for fasteners within the same fastener configuration.

Cook, Joseph S., Jr.↗
NASA NTRS1997

Bevel Gear Driver and Method Having Torque Limit Selection

Methods and apparatus are provided for a torque driver including an axially displaceable gear with a biasing assembly to bias the displaceable gear into an engagement position. A rotatable cap is provided with a micrometer dial to select a desired output torque. An intermediate bevel gear assembly is disposed between an input gear and an output gear. A gear tooth profile provides a separation force that overcomes the bias to limit torque at a desired torque limit. The torque limit is adjustable and may be adjusted manually or automatically depending on the type of biasing assembly provided. A clutch assembly automatically limits axial force applied to a fastener by the operator to avoid alteration of the desired torque limit.

Cook, Joseph S., Jr.↗
NASA NTRS2000

Experimental Investigation of Pool Boiling Heat Transfer Enhancement in Microgravity in the Presence of Electric Fields

The research carried out in the Heat Transfer Laboratory of the Johns Hopkins University was motivated by previous studies indicating that in terrestrial applications nucleate boiling heat transfer can be increased by a factor of 50 when compared to values obtained for the same system without electric fields. Imposing an external electric field holds the promise to improve pool boiling heat transfer in low gravity, since a phase separation force other than gravity is introduced. The influence of electric fields on bubble formation has been investigated both experimentally and theoretically.

Herman, C.↗
NASA NTRS2008

Gas Strut Separation Alternative for Ares I

This paper presents a design alternative and the rationale for a stage separation system based on Metering Adiabatic Gas Struts (MAG Struts) for the Ares 1 launch vehicle. The MAG Strut separation system was proposed as an alternative to the current Ares 1 separation system, which relies on small solid rocket motors to provide the main separation force. This paper will describe technical issues that were addressed during the trade study and present a conceptual design of the strut system that best resolved the issues. Needed development testing and programmatic considerations will be addressed as part of the paper.

Floyd, Brian↗
NASA NTRS1976

Integral fan/water separator

Centrifugal force created by rotating fan wheel separates moisture from gas. Lightweight portable unit can be worn with pressurized suit, where it will remove moisture that accumulates from breathing and perspiration.

Johnson, R. L.↗
DOE OSTI2024

The Driving Force Controls Charge Separation Distance in Solid-State Organic Donor/Acceptors

In this work, charge pairs of varying separation distance are interpreted from photoinduced absorption detected magnetic resonance (PADMR) spectroscopy of organic, small molecule dilute donor/acceptor thin films. We report that a donor/acceptor film that generates few free charges at room temperature yet has a relatively large, calculated driving force for electron transfer generates a large concentration of tightly bound CT states when measured with PADMR. These states are markedly absent in films with smaller driving forces yet higher free charge yields which instead only show charge-separated state signals with weaker spin coupling. We interpret this result to be in support of a hypothesis where a larger reorganization energy associated with charge transfer to tightly bound CT states means that they are primarily generated in systems far from the Marcus optimum for free charge yield. And the highest free charge yielding systems instead predominantly undergo long-range charge separation into the acceptor host.

charge separation↗
NASA NTRS1992

Computations of the unsteady flow about a generic wing/pylon/finned-store configuration

An overset grid approach is used to carry out a set of computations of the unsteady flow about a generic wing, pylon, and finned-store configuration. The geometry, discretization procedure, and governing equations are presented. Thin-layer Navier-Stokes solutions are presented for four store separation cases: store in carriage position, store at two different separation positions, and a time-accurate simulation of the forced store separation from the wing pylon carriage. Computational results are compared with wind tunnel data for the three 'static store' cases. Dynamic loads and trajectory data are presented for the forced separation case.

Meakin, Robert L.↗