Dynamic Simulation and Experimental Research of High Pressure Pneumatic Valve in Gas-Driven Light Gas Gun

2013 ◽  
Vol 365-366 ◽  
pp. 289-293
Author(s):  
Yang Liu ◽  
Xiao Dong Song ◽  
Xiao Xian Yao ◽  
Kun Li
Keyword(s):  
High Pressure ◽  
Delay Time ◽  
Experimental Tests ◽  
Response Characteristic ◽  
Test Bed ◽  
Supply Circuit ◽  
Electromagnetic Valve ◽  
Pneumatic Valve ◽  
Gas Gun ◽  
Gas Supply

Use gas-driven light gas gun is one of the techniques extensively used to achieve hypervelocity projectiles. The device was made up of a compressed gas gun as the first-stage drive. A new type high pressure pneumatic injecting system of gas-driven light gas gun for hypervelocity launching is introduced. As a critical component of the injecting system, the high pressure pneumatic valve was designed. Functions of the pneumatic valve were preserved and relevant techniques were discussed. Besides, a high pressure pneumatic mass flow control test-bed using inert medium was built in order to study the dynamic response characteristic of high pressure pneumatic valve in gas-driven light gas gun. To ascertain the response delay time of the valve, several turn-on and turn-off experimental tests of the valve were initiated. The results suggest that: the pressure of pneumatic electromagnetic valve gas supply circuit seriously influenced the properties of high pressure pneumatic valve; the mean delay time of the high pressure pneumatic valve was 190ms approximately at 6.5MPa gas pressure of the pneumatic electromagnetic valve gas supply circuit.

scholarly journals Numerical Evaluation of a Light-Gas Gun Facility for Impact Test

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
C. Rahner ◽  
H. A. Al-Qureshi ◽  
D. Stainer ◽  
D. Hotza ◽  
M. C. Fredel
Keyword(s):  
High Velocity ◽  
Numerical Evaluation ◽  
Impact Test ◽  
Experimental Tests ◽  
Reservoir Pressure ◽  
One Stage ◽  
Gas Gun ◽  
Numerical Predictions ◽  
High Velocity Impacts ◽  
Different Types

Experimental tests which match the application conditions might be used to properly evaluate materials for specific applications. High velocity impacts can be simulated using light-gas gun facilities, which come in different types and complexities. In this work different setups for a one-stage light-gas gun facility have been numerically analyzed in order to evaluate their suitability for testing materials and composites used as armor protection. A maximal barrel length of 6 m and a maximal reservoir pressure of a standard industrial gas bottle (20 MPa) were chosen as limitations. The numerical predictions show that it is not possible to accelerate the projectile directly to the desired velocity with nitrogen, helium, or hydrogen as propellant gas. When using a sabot corresponding to a higher bore diameter, the necessary velocity is achievable with helium and hydrogen gases.

Improved Third Generation Peristaltic Crawler for Removal of High-Level Waste Plugs in United States Department of Energy Hanford Site Pipelines

2013 ◽  
Author(s):  
Gabriela Vazquez ◽  
Tomas Pribanic
Keyword(s):  
Fatigue Testing ◽  
Experimental Tests ◽  
Department Of Energy ◽  
High Level Waste ◽  
Pipeline System ◽  
United States Department ◽  
Third Generation ◽  
Test Bed ◽  
Hanford Site ◽  
High Level

There are approximately 56 million gallons (212km3) of high level waste (HLW) at the U.S. Department of Energy (DOE) Hanford Site. It is scheduled that by the year 2040, the HLW is to be completely transferred to secure double-shell tanks (DST) from the leaking single-tanks (SST) via transfer pipeline system. Blockages have formed inside the pipes during transport because of the variety in composition and characteristics of the waste. These full and partial plugs delay waste transfers and require manual intervention to repair, therefore are extremely expensive, consuming millions of dollars and further threatening the environment. To successfully continue the transfer of waste through the pipelines, DOE site engineers are in need of a technology that can accurately locate the blockages and unplug the pipelines. In this study, the proposed solution to remediate blockages formed in pipelines is the use of a peristaltic crawler: a pneumatically/hydraulically operated device that propels itself in a worm-like motion through sequential fluctuations of pressure in its air cavities. The crawler is also equipped with a high-pressure water nozzle used to clear blockages inside the pipelines. The crawler is now in its third generation. Previous generations showed limitations in its durability, speed, and maneuverability. Latest improvements include an automation of sequence that prevents kickback, a front-mounted inspection camera for visual feedback, and a thinner wall outer bellow for improved maneuverability. Different experimental tests were conducted to evaluate the improvements of crawler relative to its predecessors using a pipeline test-bed assembly. Anchor force tests, unplugging tests, and fatigue testing for both the bellow and rubber rims have yet to be conducted and thus results are not presented in this research. Experiments tested bellow force and response, cornering maneuverability, and straight line navigational speed. The design concept and experimental test results are reported.

Interpretation of Flow Reactor Based Ignition Delay Measurements

2009 ◽  
Author(s):  
David Beerer ◽  
Vincent McDonell ◽  
Scott Samuelsen ◽  
Leonard Angello
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Residence Time ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Flow Reactor ◽  
Ignition Delay Times ◽  
Delay Times ◽  
Recirculation Zones

Compositional variation of global gas supplies is becoming a growing concern. Both the range and rate-of-change of this variation is expected to increase as global markets for Liquefied Natural Gas (LNG) continue to expand. Greater fuel composition variation poses increased operational risk to gas turbine engines employing lean premixed combustion systems. Information on ignition delay at high pressure and intermediate temperatures is valuable for lean premixed gas turbine design. In order to avoid autoignition of the fuel/air mixture within the premixer, the ignition delay time must be greater than the residence time. Evaluating the residence time is not a straight forward task because of the complex aerodynamics due to recirculation zones, separation regions, and boundary layers effects which may create regions where the local residence times may be longer than the bulk or average residence time. Additionally, reliable experiments on ignition delay at gas turbine conditions are difficult to conduct. Devices for testing include shock tubes, rapid compression machine and flow reactors. In a flow reactor ignition delay data are commonly determined by measuring the distance from the fuel injector to the reaction front (L) and dividing it by the bulk or average flow velocity (U) under steady flow conditions to obtain a bulk residence time which is assumed to be equal to the ignition delay time. However this method is susceptible to the same boundary layer effects or recirculation zones found in premixers. An alternative method for obtaining ignition delay data in a flow reactor is presented herein, where ignition delay times are obtained by measuring the time difference between fuel injection and ignition using high speed instrumentation. Ignition delay times for methane, ethane and propane at gas turbine conditions were in the range of 40–500 ms. The results obtained show excellent agreement with recently proposed chemical mechanisms for hydrocarbons at low temperature/high pressure conditions.

A High-Pressure Pulsed Water Jet Cutting System by Means of Water Hammer in a Convergent Pipeline

2003 ◽  
Author(s):  
Koji Yamane ◽  
Hiromitsu Sasaki ◽  
Yuzuru Shimamoto
Keyword(s):  
High Pressure ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Water Jet ◽  
Injection System ◽  
Source Pressure ◽  
Electromagnetic Valve ◽  
Water Jet Cutting ◽  
Pulsed Water Jet ◽  
Cutting System

One of the authors has developed a high-pressure fuel injection system using an oil hammer for diesel engines in 1993. In the present study, we applied this novel principle of the fuel injection system to the water-jet cutting system, and a pulsed water jet cutting system by means of water hammer in convergent pipeline caused by strong spool acceleration was developed. The system consisted of a pump having a small size plunger and spool, a convergent pipeline, and automatic injector having a hole-type nozzle with a small orifice. This pump, generating strong compression waves at the convergent pipeline inlet by strong acceleration of spool and plunger, is controlled by the low source oil pressure and electromagnetic valve. The wave propagated in the convergent pipeline is dynamically intensified by water hammering in the pipeline. High pressure is then developed at the nozzle. The injection pressure and injection frequency are fully controllable by the source pressure, and by the valve-opening frequency of the electromagnetic valve (EMPV). A computer simulation demonstrated that an operation and the injection pressure are satisfactory as a water jet cutting system. It is shown that a pressure of 140 MPa is obtained in nozzle inlet by a source pressure of 11.8MPa in experiments. The dimension of the nozzle orifice was determined by visualizing the spray origin using a laser-sheet imaging technique. Stagnation force and its spectrum of water jet on work was measured to evaluate effects of injection period and standoff distance on punching time and area. Practical feasibility of water jet cutting system was demonstrated by cutting/punching tests for soft/no-heating materials or metal plates and by paint removing tests.

Estimation of Ballistic Limit Velocities for Woven Composite Beams

2009 ◽  
Author(s):  
E. Sevkat ◽  
B. M. Liaw ◽  
F. Delale ◽  
B. B. Raju
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Damage Model ◽  
Experimental Tests ◽  
Composite Beams ◽  
Ballistic Limit ◽  
Gas Gun ◽  
Graphite Fibers ◽  
Ballistic Limit Velocity ◽  
Good Agreement

This paper presents an experimental and numerical study to estimate ballistic limit velocity, V50, of plain-weave hybrid S2 glass-IM7 graphite fibers/toughened SC-79 resin (cured at 177°C) composite beams. The tests were conducted on hybrid S2 glass-IM7 graphite fibers/toughened SC-79 resin and nonhybrid S2 glass-fiber/toughened SC-79 resin composites beams using high-speed gas-gun. The ballistic impact tests were then modeled using 3-D dynamic nonlinear finite element (FE) code, LS-DYNA, modified with a proposed user-defined nonlinear-orthotropic damage model. The ballistic limit velocities, V50, for both composite beams were then estimated using (a) only experimental tests, (b) combined experimental and numerical tests, (c) FE calculated residual velocities, and (d) FE calculated residual and transferred energies. For each type of composite beams, the parameters for the well-known Lambert-Jones equation were also computed. Good agreement between experimental and numerical results was observed.

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