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Title: INVESTIGATION OF THE HIGH INTENSITY ARC TECHNIQUE FOR MATERIALS TESTING. Period Covered: April 1957 to March 1958

Abstract

Basic studies performed during the second year of a two-year program to evaluate the adaptability of the high-intensity arc flame as a testing medium are described. A more stable and controllable configuration of arc operation, featuring a triple cathode, was developed. The pulse methed of measuring tail flame velocity was improved aud the range of measurements extended by using a more powerful electronic pulsing device. A definite peak in the curve of instantaneous velocity versus axial distance along the flame was observed which appeared to shift farther away from the crater as the ambient pressure is reduced. The maximum velocity achieved was approximately 70,000 cm/sec. The mass density of the flame was measured by means of a dynamometric technique using a disk-shaped model. The results showed a wide discrepancy with values predicted from the ideal gas law. Extensive heat flux measurements were made by calorimetric methods to determine the rate of energy absorption as a function of power input, ambient pressure, and location. The maximum heat absorption rate measured was 1.5 kw/cm/sup 2/. Abnormally high heat transfer coefficients were indicated for surfaces in contact with a plasma flame. A photodensitometer method was used to indicate temperature gradients within the flame.more » These results and earlier temperature measurements are discussed. Several flow visualization techniques were utilized to determine flow patterns of the arc plasma in the vicinity of solid objects. Direct and schlieren photography showed an abnormally thick boundry layer for the flow of plasma near the models; a possible explanation is offered. Finally, attempts were made to measure thermal diffusivities of copper, graphite, molybdenum, and tungsten by inserting appropriate specimens in the flame. Results indicate that the technique of measurement requires further development to obtain reliable measurements using a plasma flame. (auth)« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Vitro Labs., West Orange, N.J.
OSTI Identifier:
4274977
Report Number(s):
WADC-TR-58-142; AD-205364
NSA Number:
NSA-13-005808
DOE Contract Number:
AF33(616)-3669
Resource Type:
Technical Report
Resource Relation:
Other Information: Project title: MATERIALS ANALYSIS AND EVALUATION TECHNIQUES. Task title: THERMODYNAMICS AND HEAT TRANSFER. Orig. Receipt Date: 31-DEC-59
Country of Publication:
United States
Language:
English
Subject:
PHYSICS AND MATHEMATICS; CALORIMETERS; CATHODES; COMBUSTION; CONFIGURATION; COPPER; DENSITY; ELECTRIC ARCS; ELECTRONIC EQUIPMENT; EQUATIONS; GAS FLOW; GASES; GRAPHITE; HEAT TRANSFER; LAYERS; MATERIALS TESTING; MEASURED VALUES; MOLYBDENUM; OPERATION; PHOTOGRAPHY; PLASMA; PRESSURE; PULSES; SOLIDS; SURFACES; TEMPERATURE; THERMAL DIFFUSION; THERMODYNAMICS; TUNGSTEN; VELOCITY

Citation Formats

Sheer, C., Fitz, C.D., Mead, L.H., Holmgren, J.D., Rothacker, D.L., and Allmand, D. INVESTIGATION OF THE HIGH INTENSITY ARC TECHNIQUE FOR MATERIALS TESTING. Period Covered: April 1957 to March 1958. United States: N. p., 1958. Web.
Sheer, C., Fitz, C.D., Mead, L.H., Holmgren, J.D., Rothacker, D.L., & Allmand, D. INVESTIGATION OF THE HIGH INTENSITY ARC TECHNIQUE FOR MATERIALS TESTING. Period Covered: April 1957 to March 1958. United States.
Sheer, C., Fitz, C.D., Mead, L.H., Holmgren, J.D., Rothacker, D.L., and Allmand, D. Sat . "INVESTIGATION OF THE HIGH INTENSITY ARC TECHNIQUE FOR MATERIALS TESTING. Period Covered: April 1957 to March 1958". United States. doi:.
@article{osti_4274977,
title = {INVESTIGATION OF THE HIGH INTENSITY ARC TECHNIQUE FOR MATERIALS TESTING. Period Covered: April 1957 to March 1958},
author = {Sheer, C. and Fitz, C.D. and Mead, L.H. and Holmgren, J.D. and Rothacker, D.L. and Allmand, D.},
abstractNote = {Basic studies performed during the second year of a two-year program to evaluate the adaptability of the high-intensity arc flame as a testing medium are described. A more stable and controllable configuration of arc operation, featuring a triple cathode, was developed. The pulse methed of measuring tail flame velocity was improved aud the range of measurements extended by using a more powerful electronic pulsing device. A definite peak in the curve of instantaneous velocity versus axial distance along the flame was observed which appeared to shift farther away from the crater as the ambient pressure is reduced. The maximum velocity achieved was approximately 70,000 cm/sec. The mass density of the flame was measured by means of a dynamometric technique using a disk-shaped model. The results showed a wide discrepancy with values predicted from the ideal gas law. Extensive heat flux measurements were made by calorimetric methods to determine the rate of energy absorption as a function of power input, ambient pressure, and location. The maximum heat absorption rate measured was 1.5 kw/cm/sup 2/. Abnormally high heat transfer coefficients were indicated for surfaces in contact with a plasma flame. A photodensitometer method was used to indicate temperature gradients within the flame. These results and earlier temperature measurements are discussed. Several flow visualization techniques were utilized to determine flow patterns of the arc plasma in the vicinity of solid objects. Direct and schlieren photography showed an abnormally thick boundry layer for the flow of plasma near the models; a possible explanation is offered. Finally, attempts were made to measure thermal diffusivities of copper, graphite, molybdenum, and tungsten by inserting appropriate specimens in the flame. Results indicate that the technique of measurement requires further development to obtain reliable measurements using a plasma flame. (auth)},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Mar 01 00:00:00 EST 1958},
month = {Sat Mar 01 00:00:00 EST 1958}
}

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  • Studies were made on the tail flame of a highintensity electric arc to determine its suitability as a medium for testing materials under sustained hightemperature gaseous flow. An electrode geometry for stable operation was established. Measurements are reported on the temperature and velocity distribution in the tail flame at various pressures. Observations on the electrodynamic, magnetic, and thermodynamic properties of the tail flame were made. Surface heat flux rates were measured at 1.0 and 0.1 atmospheres on copper bodies in thermal equalibrium Diffusivity measurements were made in the taail flame on OFHC copper and graphite plates. (W.D.M.)
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  • Austenitic Cr-Mn-C -N steels containing various combinntions of V, Nb, W, and/or Mo had, after heat treating, room- and elevated-temperature tensile properties and creep-rupture strengths that compared fuvorably with those of such superalloys as A286 and Inco 901. Proper selection of composition and heattreatment enabled development of adequate ductility in tension and creep rupture although a marked decrease in impact properties could not be avoided. Calcium additions improved the creep rupture strength of CrMn-C-N steels thnt did not contain additions of strengthening elements (V, Hb, Mo, and W). A silicon addition of about 2% to high-chromium Cr-Mn-C-N steels increased themore » oxidation resistance at 2000 and 2200 F so that these steels compared favorably with Type 310 stainless steel. Both strengthened and unstrengthened austenitic Cr-Mn- C- N steels could be hot-rolled to sheets without the formation of edge cracks or surface defects, but rolling pressures higher than those for Type 310 stainless steel were required. (auth)« less