Theoretical Estimate of Cooling Time of a Liquid Hydrogen Tank during Structural Tests

2021 ◽  
pp. 83-89
Author(s):  
N.O. Borschev ◽  
O.A. Yuranev
Keyword(s):  
Boiling Point ◽  
Theoretical Estimate ◽  
Experimental Tests ◽  
Liquid Hydrogen ◽  
Cooling Time ◽  
Space Vehicles ◽  
Gaseous State ◽  
Temperature State ◽  
Structural Tests ◽  
Cryogenic Propellants

Russian enterprises continue developing rocket and space vehicles based on cryogenic propellants, i.e. liquid hydrogen, oxygen, and methane. Hence, the issues of fuel tanks’ thermal strength are increasingly important. During structural tests, the operating temperatures of the test object should be simulated, since the temperature condition affects the strength and rigidity of the structure. Consequently, during ground-based experimental tests, hydrogen tanks must be cooled down to 20 K, the boiling point of hydrogen. JSC TsNIIMash is developing a helium system capable of cooling large-sized structures to a temperature of 20 K. Helium can be used in a gaseous state to cool down the structure, since the boiling point of helium, 4 K, is lower than the boiling point of hydrogen. Until now, the tanks were cooled only by filling with liquid nitrogen, therefore the temperature state of the tanks during the tests was simulated only for this case. In order to determine the applicability of the method developed, the cooling time of large-sized containers was estimated by cooling a hydrogen tank, which by its dimensions is typical for an advanced medium-class second stage launcher, to 20 K by gaseous helium.

A Novel Approach for Designing Boltless Connectors - Example on a New Drilling Riser Connector

2021 ◽  
Author(s):  
Eleonore Roguet ◽  
Emmanuel Persent ◽  
Daniel Averbuch
Keyword(s):  
Finite Element ◽  
Design Process ◽  
Load Transfer ◽  
Design Method ◽  
Experimental Tests ◽  
New Product ◽  
Block Type ◽  
Finite Element Analyses ◽  
Novel Approach ◽  
Structural Tests

Abstract A new method which uses elastic and elasto-plastic Finite Element analyses is developed to design a double breech-block type connector. All relevant criteria proposed by API16F are fulfilled. In addition, plastic and bearing criteria have been added to support the use of lugs for load transfer in the connector. The proposed methodology has been applied and validated through experimental tests at different scales and in particular on laboratory specimens and small-scaled connectors. Based on these last structural tests, a safety factor of almost 8 was obtained for the design method on small-scaled connectors. Prototype tests at scale 1:1 allowed the methodology to be fully validated and a new product to be qualified. Certification bodies validated the whole design process, the employed methodology and the new connector.

scholarly journals Tempcore Process Simulator to Analyze Microstructural Evolution of Quenched and Tempered Rebar

2019 ◽  
Vol 9 (14) ◽  
pp. 2938 ◽  
Author(s):  
Chun Su Park ◽  
Hyang Jun Yi ◽  
Yong-Tae Kim ◽  
Sang Wook Han ◽  
Taekyung Lee ◽  
...  
Keyword(s):  
Microstructural Evolution ◽  
Water Pressure ◽  
Experimental Tests ◽  
Cooling Time ◽  
Shop Floor ◽  
Vacuum Induction Furnace ◽  
Chemical Compositions ◽  
High Degree ◽  
Tempcore Process ◽  
Process Simulator

Tempcore process simulator (TPS) has been developed in this study to analyze the microstructural evolution of quenched and tempered rebar. There has been an increasing need to relate the complex microstructures to the resulting properties of quenched and tempered rebar. However, information on such relationships typically requires precise thermal histories imposed on the workpiece. Therefore, TPS, capable of simulating the Tempcore process, has been developed to produce high-fidelity data. TPS mainly consists of a vacuum induction furnace, pilot rolling mill, box furnace, and cooling unit to simulate shop floor operations. A series of experimental tests were successfully carried out with various parameters, such as reheating temperature, water flow, water pressure, and cooling time. The effects of chemical compositions and cooling time on the microstructural evolution and mechanical properties of quenched and tempered rebar have been analyzed to validate the performance of TPS. The results show that TPS can simulate the Tempcore process with a high degree of fidelity and reliability.

Lethal Helium Intoxication. Determining the Context, Cause and Time of Death

2018 ◽  
Vol 69 (10) ◽  
pp. 2816-2818
Author(s):  
Andrei Scripcaru ◽  
Anton Knieling ◽  
Cristiana Manea ◽  
Dragos Valentin Crauciuc ◽  
Sofia Mihaela David ◽  
...  
Keyword(s):  
Melting Point ◽  
Atomic Number ◽  
Boiling Point ◽  
Chemical Element ◽  
Chemical Elements ◽  
Extreme Conditions ◽  
Time Of Death ◽  
Gaseous State ◽  
Suicide Rates

Helium is the chemical element with atomic number 2, represented by the symbol He. It is an inert, colorless, odorless, insipid monoatomic gas. It has the lowest boiling point and the lowest melting point among the chemical elements and appears only in gaseous state, except for extreme conditions. The use of helium for suicidal purposes is extremely rare. In Romania, suicide has a frequency of 12 per 100,000 inhabitants, which classifies us in the category of countries with low suicide rates. As methods, men use hanging most often while women use more softer methods such as poisoning. Helium is rarely used for suicidal purposes because it is relatively difficult to obtain. Basically, it is not poisoning in the true sense of the word, but rather the substitution of oxygen with helium, which cannot be carried by hemoglobin, and thus transport asphyxia occurs. At the end of the paper we shall exemplify a case of helium poisoning for suicide purposes, purchased from a cylinder for inflating balloons.

scholarly journals Tractor accelerated test on test rig

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
M. Mattetti ◽  
Giovanni Molari ◽  
A. Vertua ◽  
A. Guarnieri
Keyword(s):  
Real Life ◽  
Weather Condition ◽  
Experimental Tests ◽  
Acceleration Factor ◽  
Test Rig ◽  
The Real ◽  
Structural Part ◽  
Ground Testing ◽  
Post Test ◽  
Structural Tests

The experimental tests performed to validate a tractor prototype before its production, need a substantial financial and time commitment. The tests could be reduced using accelerated tests able to reproduce on the structural part of the tractor, the same damage produced on the tractor during real life in a reduced time. These tests were usually performed reproducing a particular harsh condition a defined number of times, as for example using a bumpy road on track to carry out the test in any weather condition. Using these procedures the loads applied on the tractor structure are different with respect to those obtained during the real use, with the risk to apply loads hard to find in reality. Recently it has been demonstrated how, using the methodologies designed for cars, it is possible to also expedite the structural tests for tractors. In particular, automotive proving grounds were recently successfully used with tractors to perform accelerated structural tests able to reproduce the real use of the machine with an acceleration factor higher than that obtained with the traditional methods. However, the acceleration factor obtained with a tractor on proving grounds is in any case reduced due to the reduced speed of the tractors with respect to cars. In this context, the goal of the paper is to show the development of a methodology to perform an accelerated structural test on a medium power tractor using a 4 post test rig. In particular, several proving ground testing conditions have been performed to measure the loads on the tractor. The loads obtained were then edited to remove the not damaging portion of signals, and finally the loads obtained were reproduced in a 4 post test rig. The methodology proposed could be a valid alternative to the use of a proving ground to reproduce accelerated structural tests on tractors.

scholarly journals The boiling point of liquid hydrogen, determined by hydrogen and helium gas thermometers

1901 ◽  
Vol 68 (442-450) ◽  
pp. 44-54 ◽  
Keyword(s):  
Boiling Point ◽  
Liquid Hydrogen ◽  
Platinum Resistance Thermometer ◽  
Platinum Resistance ◽  
Resistance Thermometer ◽  
Helium Gas ◽  
Empirical Law

In a former paper it was shown that a platinum-resistance thermometer gave for the boiling point of hydrogen - 238°-4 C., or 34°-6 absolute. As this value depended on an empirical law correlating temperature and resistance, which might break down at such an exceptional temperature, and was in any case deduced by a large extrapolation, it became necessary to have recourse to the gas thermometer.

Neutron Radiography of Condensation and Evaporation of Hydrogen in a Cryogenic Condition

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Kishan Bellur ◽  
Ezequiel Medici ◽  
Jeffrey Allen ◽  
Jimes Hermanson ◽  
Arun Tamilarasan ◽  
...  
Keyword(s):  
Cross Section ◽  
Neutron Radiography ◽  
High Sensitivity ◽  
Liquid Hydrogen ◽  
Neutron Imaging ◽  
Test Cell ◽  
Inner Diameter ◽  
Temperature And Pressure ◽  
Cryogenic Propellants ◽  
Cryogenic Conditions

The condensation and evaporation of hydrogen under cryogenic conditions is visualized by using neutron imaging at the BT-2 Beam Facility at the National Institute of Standards and Technology (NIST). The condensation and evaporation are controlled by adjusting temperature (20 K ~ 23 K) and pressure (1.3 ~ 1.95 bar absolute). The hydrogen contained in the aluminum test cell inside the cryostat has a large attenuation coefficient due to its large scattering cross section. The high sensitivity of neutron radiography to hydrogen allows the visualization of a meniscus and a contact line of evaporating hydrogenated cryogenic propellants. The graphic represents the temperature, pressure and corresponding images of liquid hydrogen in the test cell. The test cell is made of Aluminum 6061 with an inner diameter of 12 mm. The captured images are then median filtered and post-processed in order to find the volume of liquid hydrogen in the test cell as a function of time. The condensation/evaporation rates obtained from neutron imaging along with corresponding temperature and pressure are used to validate the evaporation model being developed by the authors.

scholarly journals Design of New Carbon-Phenolic Ablators: Manufacturing, Plasma Wind Tunnel Tests and Finite Element Model Rebuilding

2021 ◽  
Author(s):  
L. Paglia ◽  
V. Genova ◽  
J. Tirillò ◽  
C. Bartuli ◽  
A. Simone ◽  
...  
Keyword(s):  
Heat Flux ◽  
Finite Element ◽  
Wind Tunnel ◽  
Finite Element Model ◽  
Thermal Protection ◽  
Experimental Tests ◽  
Element Model ◽  
High Energy ◽  
Space Vehicles ◽  
Mechanical And Thermal Properties

AbstractAblative materials represent a widespread solution for shielding space vehicles from overheating during a reentry phase in atmosphere where the high heating fluxes and the consequent high temperatures cannot be compatible with the vehicle structure and with the safety of the payload and/or the crew. In this work, two different kinds of carbon-phenolic ablators with a density of 0.3 g/cm3 were manufactured and their mechanical and thermal properties were experimentally evaluated. The thermal protection performances of the developed ablators were assessed in a hypersonic plasma wind tunnel facility, setting representative enthalpy and heat flux conditions (6 and 13 MW/m2), consistent with atmospheric reentry missions from high energy orbits. Data of the experimental tests were compared with the results obtained by a finite element model built up for these materials with the commercial software SAMCEF Amaryllis. All results enlighten the good performances of the ablators under severe heat flux conditions and outline their operating limits.

Sign in / Sign up

Export Citation Format

Share Document