scholarly journals Innovative Cooling for Rocket Combustion Chambers

2020 ◽  
pp. 51-64
Author(s):  
Jonas Peichl ◽  
Andreas Schwab ◽  
Markus Selzer ◽  
Hannah Böhrk ◽  
Jens von Wolfersdorf
Keyword(s):  
Gas Flow ◽  
Rocket Engine ◽  
Ceramic Matrix Composite ◽  
Measurement Data ◽  
Life Time ◽  
Sample Surface ◽  
Transportation Systems ◽  
Wake Flow ◽  
Experimental Investigations ◽  
Combustion Chambers

Abstract Transpiration cooling in combination with permeable ceramic-matrix composite materials is an innovative cooling method for rocket engine combustion chambers, while providing high cooling efficiency as well as enhancing engine life time as demanded for future space transportation systems. In order to develop methods and tools for designing transpiration cooled systems, fundamental experimental investigations were performed. An experimental setup consisting of a serial arrangement of four porous carbon fiber reinforced carbon (C/C) samples is exposed to a hot gas flow. Perfused with cold air, the third sample is unperfused in order to assess the wake flow development over the uncooled sample as well as the rebuilding of the coolant layer. Hereby, the focus is on the temperature boundary layer, using a combined temperature/pitot probe. Additionally, the sample surface temperature distribution was measured using IR imaging. The experiments are supported by numerical simulations which are showing a good agreement with measurement data for low blowing ratios.

Experimental Inverstigations On the Pressure Fluctuations in the Sealing Gap of Dry Gas Seals with Embedded Pressure Sensors

2021 ◽  
Author(s):  
Jingjing Luo ◽  
Dieter Brillert
Keyword(s):  
High Speed ◽  
Gas Flow ◽  
Static Pressure ◽  
Pressure Sensors ◽  
Operating Conditions ◽  
Test Facility ◽  
Experimental Investigations ◽  
Mechanical Seals ◽  
Process Gas ◽  
Sealing Gap

Abstract Dry gas lubricated non-contacting mechanical seals (DGS), most commonly found in centrifugal compressors, prevent the process gas flow into the atmosphere. Especially when high speed is combined with high pressure, DGS is the preferred choice over other sealing alternatives. In order to investigate the flow field in the sealing gap and to facilitate the numerical prediction of the seal performance, a dedicated test facility is developed to carry out the measurement of key parameters in the gas film. Gas in the sealing film varies according to the seal inlet pressure, and the thickness of gas film depends on this fluctuated pressure. In this paper, the test facility, measurement methods and the first results of static pressure measurements in the sealing gap of the DGS obtained in the described test facility are presented. An industry DGS with three-dimensional grooves on the surface of the rotating ring, where experimental investigations take place, is used. The static pressure in the gas film is measured, up to 20 bar and 8,100 rpm, by several high frequency ultraminiature pressure transducers embedded into the stationary ring. The experimental results are discussed and compared with the numerical model programmed in MATLAB, the characteristic and magnitude of which have a good agreement with the numerical simulations. It suggests the feasibility of measuring pressure profiles of the standard industry DGS under pressurized dynamic operating conditions without altering the key components of the seal and thereby affecting the seal performance.

scholarly journals Experimental investigations of CO2 seepage behaviorin naturally fractured coal under hydro-thermal-mechanical conditions

2021 ◽  
Vol 25 (6 Part B) ◽  
pp. 4651-4658
Author(s):  
Teng Teng ◽  
Xiaoyan Zhu ◽  
Yu-Ming Wang ◽  
Chao-Yang Ren
Keyword(s):  
Gas Flow ◽  
Confining Pressure ◽  
Gas Pressure ◽  
Experimental Investigations ◽  
Permeability Evolution ◽  
Coal Permeability ◽  
Naturally Fractured ◽  
Series Of Experiments ◽  
Fractured Coal ◽  
Increasing Temperature

Gas-flow in coal or rock is hypersensitive to the changes of temperature, confin?ing pressure and gas pressure. This paper implemented a series of experiments to observe the seepage behavior, especially the permeability evolution of CO2 in naturally fractured coal sample under coupled hydro-thermal-mechanical conditions. The experimental results show that coal permeability increases exponentially with the increasing gas pressure, and tends to be linear when the confining pressure is high. Coal permeability decreases exponentially with the increasing confining pressure. Coal permeability decreases with the increasing temperature generally, but it may bounce up when the temperature rises to high. The results provide reference for the projects of coal gas extraction and carbon dioxide geological sequestration.

Experiences on production - usage reasoned malfunctions & development of  X-ray tubes used in science and their effects on sediment measurements

2021 ◽  
Author(s):  
Dursun Acar ◽  
Namık Çagatay ◽  
Ş. Can Genç ◽  
K. Kadir Eriş ◽  
Demet Biltekin ◽  
...  
Keyword(s):  
Low Voltage ◽  
Measurement Data ◽  
Electric Circuit ◽  
Sample Surface ◽  
Open Circuit ◽  
Silicone Grease ◽  
X Ray ◽  
Negative Results ◽  
Contact Points ◽  
Measured Sample

<p>Surface fractures at the filament of X-ray tube increase more with metal fatique or wrong cooling  and heating processes. Fractured filament continue to work as repeating open circuit positions in random times with  turning fully conductive state in short time. We are explaining how open circuit flashes at the filament providing wrong measurement results. Their low voltage electric circuit conductive problems  repeat in milliseconds periods. At  the results, it gives the impression of healthy measurement values. Because that the measured sample absorbs photonic energy and direct it to neighbouring elements in continuous element  electron scattering  circulations , by the way that delayed secondary electron energy scatters hide all electron supply extinctions on the semi broken flament wire and indirect counts  continue by the detector from coming reflection energy. ( real counts are not from exact beam  target of sample surface during energy deprivations , and it is impossible to understand that the measurement is inaccurate because it causes similarity as discrete element counts in sedimentation layers ).  Filament voltage arcs do not warn machine with error reporting systems until to whole ruptured filament touch to anode walls or their far displaced edges of 2 broken filament positioning. Erroneous records take their place in the world of science if the lithology was not followed. We collected faulty measurement data from our experiences for indicate when and  how possible to facing such as events.</p><p>For eliminate  explained reasons at above , the tubes must be gently heated and  cooled. Excessive cooling or heating of the tubes or oxid placement and leakeage  at gasget contacts reduces the surface contact areas of the insilators with the corrosion by  condensing water around the rubber insulation gasgets , it causes cooling liquid leakage or increasing humidity at the tube housing block via following serial failures of HV unit such as increasing amounts of the broken tube events. During the replacement of insulating gasgets, enough care should be taken for gasket contact points as oiling  them with  silicone grease as a form of the thin film. High responsibility must be with continuous  result control  and reference correlations on the scientific sample. With this way we can eliminate possible  negative results by malfunctions on measurements.</p>

Results of the Study Rotor Wheels Supersonic Microturbines with a Large Angle of Rotation of the Flow

2015 ◽  
Vol 752-753 ◽  
pp. 884-889 ◽  
Author(s):  
Andrey Yu. Fershalov ◽  
Mikhail Yu. Fershalov ◽  
Yuriy Ya. Fershalov ◽  
Timofey V. Sazonov
Keyword(s):  
Mach Number ◽  
Gas Flow ◽  
Large Angle ◽  
Experimental Investigations ◽  
Flow Rates ◽  
Ratio Speed ◽  
Supersonic Gas Flow ◽  
Angle Of Rotation

The article presents the results of experimental investigations of rotor wheels supersonic microturbines with a large angle of rotation of the flow. The characteristics of the studied rotor wheels. The analysis of the results of the study ratio speed of rotor wheels, depending on the Mach number. Recommendations for the design working wheels microturbines operating at high supersonic gas flow rates.

Numerical Prediction of Erosion of Mild Steel Surfaces by Boiler Fly Ash Particles

Volume 1 ◽  
2004 ◽  
Author(s):  
John G. Mbabazi ◽  
Thomas J. Sheer
Keyword(s):  
Fly Ash ◽  
Mild Steel ◽  
Flue Gas ◽  
Gas Flow ◽  
Erosive Wear ◽  
Test Facility ◽  
Experimental Investigations ◽  
Power Station ◽  
Erosion Rates ◽  
Steel Surfaces

Fly ash particles entrained in the flue gas from boiler furnaces in coal-fired power stations can cause serious erosive wear on steel surfaces along the downstream flow path. This paper describes research into fly ash impingement erosion on such surfaces, with particular reference to the heat transfer plates in rotary regenerative air heaters. The effect of the ash particle impact velocity and impact angle on the erosive wear of mild steel surfaces was determined through experimental investigations, using three different power station ash types. The experimental data were used to calibrate a fundamentally-derived model for the prediction of erosion rates. This erosion model was incorporated into a particle-tracking CFD flow simulation of the ash-laden flue gas flow through the complex channels between corrugated air heater plates. The predicted erosion rates were compared with measured erosion rates obtained using a large accelerated-erosion test facility located at a power station. Good agreement was obtained, the predictions generally being within 20 percent of the measured values.

Biodegradation of Styrene Vapor in a Biofilter

2013 ◽  
Vol 275-277 ◽  
pp. 2329-2332 ◽  
Author(s):  
Xian Sheng Huang ◽  
Hao Wu
Keyword(s):  
Gas Flow ◽  
Experimental Investigations ◽  
Flow Rates ◽  
Operational Conditions ◽  
New Class ◽  
Filter Materials ◽  
Air Stream ◽  
Volatile Organic ◽  
Maximum Elimination Capacity ◽  
Styrene Removal

Volatile organic compounds (VOCs) are a new class of air pollutants posing threat to the environment. Newer technologies are being developed for their control among which biofiltration seem to be most attractive. Biofiltration of styrene vapor from air stream was discussed in this study. Experimental investigations were conducted on a laboratory scale biofilter, containing mixture of compost and polystyrene inert particles as the filter materials. Mixed consortium of activated sludge was used as an inoculum. The continuous performance of biofilter for styrene removal was monitored for different concentrations and flow rates. The removal efficiencies decreased at higher concentrations and higher gas flow rates. A maximum elimination capacity of 85g/(m3•h) was achieved. The response of biofilter to upset loading operation showed that the biofilm in the biofilters was quite stable and quickly adapted to adverse operational conditions.

Experimental Investigations of Laminar, Transitional to Turbulent Gas Flow in a Micro-Channel

2010 ◽  
Author(s):  
Chungpyo Hong ◽  
Toru Yamada ◽  
Yutaka Asako ◽  
Mohammad Faghri ◽  
Koichi Suzuki ◽  
...  
Keyword(s):  
Mach Number ◽  
Flow Regime ◽  
Gas Flow ◽  
Flow Characteristics ◽  
Channel Length ◽  
Transitional Flow ◽  
Experimental Investigations ◽  
Compressibility Effect ◽  
Micro Channels ◽  
Wide Range

This paper presents experimental results on flow characteristics of laminar, transitional to turbulent gas flows through micro-channels. The experiments were performed for three micro-channels. The micro-channels were etched into silicon wafers, capped with glass, and their hydraulic diameter are 69.48, 99.36 and 147.76 μm. The pressure was measured at seven locations along the channel length to determine local values of Mach number and friction factor for a wide range of flow regime from laminar to turbulent flow. Flow characteristics in transitional flow regime to turbulence were obtained. The result shows that f·Re is a function of Mach number and higher than incompressible value due to the compressibility effect. The values of f·Re were compared with f·Re correlations in available literature.

Detailed Analysis of Experimental Investigations on Boundary Layer Transition in Wake Disturbed Flow

2006 ◽  
Author(s):  
Andrea Cattanei ◽  
Pietro Zunino ◽  
Thomas Schro¨der ◽  
Bernd Stoffel ◽  
Berthold Matyschok
Keyword(s):  
Boundary Layer ◽  
Measurement Data ◽  
Boundary Layer Transition ◽  
Data Evaluation ◽  
Experimental Investigations ◽  
Layer Transition ◽  
Disturbed Flow ◽  
Time Space ◽  
Separation Bubbles ◽  
Hot Film

In the framework of a co-operation between the University of Genoa and the Darmstadt University of Technology measurement data of a former investigation at Darmstadt, comprising measurements with surface-mounted hot-film sensors on the boundary layer transition in wake disturbed flow, were transferred to Genoa, then re-evaluated and in great detail analyzed, much further than the original data evaluation. In these experimental investigations at Darmstadt, the boundary layer transition with and without transitional separation bubbles was studied on a circular cylinder in cross flow. The comparison of hot-wire traverses with the surface-mounted hot-film distributions clearly indicated that the surface-mounted hot-film technique is a very suitable measurement technique to obtain reliable information on transition and separation phenomena with both high spatial and temporal resolution. The new data evaluation techniques applied to these data at Genoa further enhanced the insight into the details of the boundary layer transition and separation process. The surface-mounted hot-film data were evaluated by means of time-space diagrams for the first three statistical moments (mean, RMS and skewness), with which the origin and the extent of unsteady separation bubbles clearly could be seen. The results obtained from these data analyses on the one hand yield a considerable enhancement of the understanding of the periodically unsteady boundary layer transition process and on the other hand they form the basis for the application of surface-mounted hot-film sensors in more complex flow situations like e.g. in cold flow multistage turbine or compressor test rigs or even in the hostile environment of real aero engine compressors or turbines.

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