Browse Topic: Pressure

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This SAE Aerospace Information Report (AIR) discusses the forms that air may take in aircraft hydraulic systems. Further, the effects of the various air forms on system operation are addressed. Recommended system design to prevent air effects and maintenance procedures to prevent and remove air are provided. Nitrogen leakage from accumulators is also a source of gas in hydraulic systems and may compose a portion of the “air” in the hydraulic system. The term “air” in this report does not differentiate between a gas composed strictly of normal atmospheric air or one that includes a mixture of additional nitrogen as well. The discussions of the report apply equally with any proportions of atmospheric air and nitrogen in the system
A-6C1 Fluids and Contamination Control Committee
This SAE Aerospace Recommended Practice (ARP) establishes a method for evaluating the particulate matter extracted from the working fluid of a hydraulic system or component using a membrane. The amount of particulate matter deposited on the membrane due to filtering a given quantity of fluid is visually compared against a standard membrane in order to provide an indication of the cleanliness level of the fluid
A-6C1 Fluids and Contamination Control Committee
From biology, to genetics, and paleontology, these fields share the DNA as a common and time-proven tool. In science, pressure may be such a tool, shared by thermodynamics, material science, and astrophysics, but not by aerodynamics. Pressure is a shorthand for a force acting perpendicular to a surface. When this surface is reduced to zero, so should the pressure. The wing area of an aircraft acts as a reference area to calculate its parasite drag coefficient. In this scenario, the parasite drag acts as a force over the wing area. If the wing area is reduced to zero, its parasite drag does not, as the fuselage is still generating parasite drag. The ratio of the parasite drag and wing area is an example of a pressure construct that uses a physically irrelevant reference area and has no absolute zero. Pressure constructs, more frequently used than pressures in aerodynamics, are a math-based parameter that preserve dimensional propriety according to the Buckingham Pi theorem but lacks a
Burgers, Phillip
During accelerations and decelerations of a race car whose engine has a wet sump, the forces generated by the vehicle’s motion cause the engine oil to vigorously shift towards the walls of the oil pan and crankcase, contributing to the phenomenon known as ‘sloshing.’ This phenomenon often leads to fluctuations in oil pressure, resulting in oil pressure surge, when the oil is pushed away from the pump pickup point. Via the logged data, the Formula UFSM FSAE Team had witnessed a recurrent lack of oil pressure in the race track during the 2023 Brazilian FSAE competition. In the AutoCross Event, the recurrence of this problem was 80% of the right corners on lateral accelerations between 0.80G and 1.30G. The average oil pressure in this condition was 0.80 bar, even reaching 0.10 bar above 5000 RPM. Therefore, it was necessary to develop a new set of baffles for the oil pan, capable of minimizing the effects of sloshing and, consequently, the oil surge. As a method of research, a test bench
Zimmermann, Natalia DiovanaJunior, Luiz Alfredo CoelhoMartins, MarioHausen, Roberto
The twin challenges of the automotive industry namely petroleum dependence and environmental pollution paved way for the development of an environmentally friendly and feasible substitute for diesel, possessing power characteristics equivalent to those of a diesel engine. Biofuel has potential as a renewable energy source, offering a more sustainable alternative to traditional fossil fuels. However, it does come with some challenges, such as varying quality and combustion properties. To enhance its performance, engines can be fine-tuned by adjusting fuel injection parameters, such as timing, pressure, and duration. Accordingly, this research article focuses on optimizing the fuel injection parameters for a CRDi engine powered by D+LPO (20% lemon peel oil and 80% diesel) biofuel, with the goal of improving both performance and emission characteristics. The experimental design matrix was generated using Design Expert-13 software, employing the I-optimal technique. Utilizing response
Saiteja, PajarlaAshok, B.
Hamdi Torun Arda Deniz Yalcinkaya Gunhan Dundar Ozgue Kaya Northumbria University, Newcastle Upon Tyne, UK
Researchers have been testing ways to continuously and more comfortably detect these tiny fluctuations in pressure. A prototype smart contact lens measures eye pressure accurately, regardless of temperature. The contact lens wirelessly transmits real-time signals about eye pressure across a wide range of temperatures
ABSTRACT The military has a unique requirement to operate in different terrains throughout the world. The ability to travel in as much varying terrain as possible provides the military greater tactical options. This requirement/need is for the tire to provide a variable footprint to allow for different ground pressure. Much of the current run-flat technology utilized by the military severely limits mobility and adds significant weight to the unsprung mass. This technology gap has allowed for the development of new run-flat tire technology. New tire technology (fig 1) has been developed that substantially increases survivability, eliminates the need for heavy run-flat inserts, significantly reduces air pressure requirements and provides full (or near full) speed capability in degraded/damaged mode (punctured tire). This run-flat technology is built directly into the tire, yet maintains the normal variable footprint of a normal pneumatic tire. This makes the tire/wheel assembly much
Capouellez, JamesPannikottu, AbrahamGerhardt, Jon
ABSTRACT The AirLift is a novel device that enables rapid stabilized extraction of injured personnel from a ground vehicle. When deployed from its pre-installed position as a seat cover, the AirLift rigidizes for stabilizing the occupant’s spine by pressurizing an inflatable panel. After extraction from the vehicle with the occupant stabilized in the seated position, the AirLift can convert to a backboard so that the occupant can be safely transported in the supine position. The inflatable panel was designed and tested to provide stiffness while also being durable and manufacturable at volume. Pressure mapping tests were also performed to demonstrate that the AirLift did not change seat comfort compared to the standard seat. Citation: A. Purekar, G. Hiemenz, P. Gillis, “AirLift: Enabling Blast Protection and Rapid, Stabilized Vehicle Extraction”, In Proceedings of the Ground Vehicle Systems Engineering and Technology Symposium (GVSETS), NDIA, Novi, MI, Aug. 11-13, 2020
Purekar, AshishHiemenz, GregoryGillis, Paula
ABSTRACT Improvised Explosive Devices (IEDs) and mines pose significant threat to military ground vehicles and soldiers in the field. Due to the severity of the forces exerted by a blast, ground vehicles may undergo multiple sub-events subsequent to an explosion, including local structural deformation of the floor, gravity flight and slam-down. The current method of choice to simulate the effect of a shallow-buried IED or mine on a Lagrangian vehicle model, is a fluid-structure interaction with the environment modelled with an Eulerian formulation (explosive, ground, air) [1]. This method, also called Arbitrary Lagrangian-Eulerian (ALE), is more expensive and involved than pure structural methods (usually pressure loads applied to the vehicle surface). However, it allows for taking into account the effect of the shape, type and size of the charge and the soil characteristics on the impulse transmitted to the vehicle. Three approaches are proposed to reduce the analytical simulation
Parthasarathy, MohanKosarek, Philip G.Santini, JulienThyagarajan, Ravi
ABSTRACT Lip seals are vital components that serve two primary purposes – keep liquids/lubricants in and keep sand/contaminants out. An additional task is to confine pressure. Test study results indicate that self-polishing Additive Abradable Graphite Coatings (AAGC’s) will protect sealed rotating components from sand, and extend lubricant maintenance interval on gearboxes, PTO’s, and the like. Citation: A. Andrew Suman, “Improve Lip Seal Performance and Increase Sand Resistance With A Low Cost Graphite Shaft Coating”, In Proceedings of the Ground Vehicle Systems Engineering and Technology Symposium (GVSETS), NDIA, Novi, MI, Aug. 13-15, 2019
Suman, AndrewSilvey, TomSmith, Zachary
This work numerically investigated the feasibility of methanol compression ignition combustion for light-duty diesel engine applications by using a glow plug (GP) to promote ignition. A comprehensive parametric study was conducted to assess the combustion characteristics depending on the GP position, the relative angle between the GP and injector, and other initial conditions. Optimal design parameters were identified. It was demonstrated that GP can enable successful ignition and combustion of methanol at the operating conditions under study. Among the many parameters considered, the relative angle between the GP and injector was found to be one of the most critical parameters in controlling the ignition and complete combustion. Increasing intake temperature promoted combustion speed and engine performance, but excessively high intake temperatures led to higher wall heat transfer loss and lower ITE. An appropriate level of the pilot injection mass was found to increase ITE, with the
Liu, XinleiSim, JaeheonRaman, VallinayagamViollet, YoannAlRamadan, Abdullah S.Cenker, EmreIm, Hong G.
A power steering system helps the heavy-duty operator move the vehicle easily with the hydraulic pump that provides the fluid pressure and facilitating adequate operation. Some failures in the power steering system are due to external and internal factors that can reduce its service life. The external factors could be identified by ocular inspection but normally, due to internal failures, it is necessary to use a hydraulic pressure flow meter. However, this device makes it impossible to detect failures caused by the selected lubricant. This work aims to investigate the causes of power steering system seizure by using the tribological wear examination process and the lubricant characterization under some actual operation conditions. The lubricant characterization was carried out in a four balls tester using fresh and used samples of a re-refined oil based ATF, SAE 15 W40 and synthetic SAE 5 W30 oils at two temperatures. In general, the results showed an unsteady friction profile with
García-Maldonado, MiguelGallardo, EzequielMozqueda-Flores, LuisVite-torres, Manuel
To gain high efficiencies and long lifetimes, polymer electrolyte membrane fuel cell systems require precise control of the relative humidity of the cathode supply air. This is usually achieved by the use of membrane humidifiers. These are passive components that transfer the product water of the cathode exhaust air to humidify the supply air. Due to the passive design, controllability is achieved via a bypass. It is possible to use map-based control strategies to avoid the use of humidity sensors. Such map-based control requires deep insights into the humidifier behavior in all possible thermodynamic operating states, including various water loads. This paper focuses on typical operating conditions of heavy-duty application at high load, specifically on the occurrence of liquid water in the cathode exhaust gas, which has not been sufficiently investigated in the literature yet. In order to simulate these conditions, we built a test rig with an optically accessible single-channel set
Mull, SophieWeiss, LukasWensing, Michael
This SAE Recommended Practice defines the system and component functions, measurement metrics, and testing methodologies for evaluating the functionality and performance of tire pressure systems for use on trailers under 26000 pounds GVWR within the known operating environments. This document is applicable to all towed trailers under 26000 pounds GVWR. Examples of towed trailers are recreational vehicle travel trailers and fifth wheels, utility trailers, cargo trailers, livestock trailers, flatbed trailers, boat trailers, and snowmobile trailers. These trailers can be equipped with one, two, or three axles with each axle supporting either two or four tires. These systems are recommended to address all tires in service as originally installed on a trailer by the OEM. This recommended practice can also be applied to external TPMS that also cover tow vehicles and trailers simultaneously. This document will focus on tire pressure systems of the monitoring type
Trailer Committee
Airflow directionality in a vehicle cabin is one of the concerns of car owners, researchers, and vehicle manufacturers. After exposed/parked in hot ambient condition for a long time, HVAC system normally takes few minutes to cool down and reach an acceptable cabin temperature for the passenger comfort. To ensure proper airflow distribution inside the cabin, the AC duct & vanes ability to direct airflow must be evaluated. Objective of this work is to propose a methodology for developing the vane design of AC system duct using CFD approach. Two different goals are attempted. Firstly, the effect of horizontal and vertical vane angle on airflow directionality is investigated with DoE approach. Then factors influencing the airflow directionality are investigated using factorial study approach. CFD based factorial analysis (L9 orthogonal array) was conducted using three components at three levels. The impact of number of horizontal vanes, number of vertical vanes and distance between them on
Mahesh, ABaskar, SubramaniyanRaju, KumarGopinathan, Nagarajan
This SAE Aerospace Recommended Practice (ARP) describes a method of conducting an endurance test using contaminated air when the applicable specification requires non-recirculation of the contaminants. The objective of the test is to determine the resistance of the engine mounted components to wear or damage caused by the contaminated air. The method described herein calls for non-recirculation of the contaminants and is intended to provide a uniform distribution of the contaminant at the inlet to the Unit Under Test (UUT). The UUT may require the use of a hydraulic fluid for actuation of components within the test unit. Contamination of the test hydraulic fluid is not part of this recommended practice. If contaminated hydraulic fluid is required by the applicable test specification, refer to MAP749
AC-9 Aircraft Environmental Systems Committee
This SAE Aerospace Information Report (AIR) provides information on air quality and some of the factors affecting the perception of cabin air quality in commercial aircraft cabin air. Also a typical safety analysis process utilizing a Functional Hazard Assessment approach is discussed
AC-9 Aircraft Environmental Systems Committee
This SAE Aerospace Standard (AS) covers combustion heaters and accessories used in, but not limited to, the following applications: a Cabin heating (all occupied regions and windshield heating) b Wing and empennage anti-icing c Engine and accessory heating (when heater is installed as part of the aircraft) d Aircraft deicing
AC-9 Aircraft Environmental Systems Committee
This SAE Aerospace Standard (AS) defines the requirements for air cycle air conditioning systems used on military air vehicles for cooling, heating, ventilation, and moisture and contamination control. General recommendations for an air conditioning system, which may include an air cycle system as a cooling source, are included in MIL-E-18927E and JSSG-2009. Air cycle air conditioning systems include those components which condition high temperature and high pressure air for delivery to occupied and equipment compartments and to electrical and electronic equipment. This document is applicable to open and closed loop air cycle systems. Definitions are contained in Section 5 of this document
AC-9 Aircraft Environmental Systems Committee
Even if huge efforts are made to push alternative mobility concepts, such as, electric cars (BEV) and fuel cell powered cars, the importance and use of liquid fuels is anticipated to stay high during the 2030s. The biomethane and synthetic natural gas (SNG) might play a major role in this context as they are raw material for chemical industry, easy to be stored via existing infrastructure, easy to distribute via existing infrastructure, and versatile energy carrier for power generation and mobile applications. Hence, biomethane and synthetic natural gas might play a major role as they are suitable for power generation as well as for mobile applications and can replace natural gas without any infrastructure changes. In this paper, we aim to understand the direct production of synthetic natural gas from CO2 and H2 in a Sabatier process based on a thermodynamic analysis as well as a multi-step kinetic approach. For this purpose, we thoroughly discuss CO2 methanation to control emission in
Mauss, Fabian
The impacts of injection pressure with a Gaussian-shaped ribbed piston bowl design for energy-assisted compression-ignition (EACI) combustion were investigated in an optically accessible engine. Three injection pressures (600, 800, and 1000 bar) were investigated for three potential first injection timings corresponding to injection timings for injection dwells of 1.5, 2.0, and 2.5 ms of a fixed second injection timing of -5.0 CAD. Reliable positioning of the hot combusted gases from the first injection near the injector tip enables mixing-controlled combustion of the second injection. Results demonstrated the EACI capabilities of pairing high injection pressures with the Gaussian-shaped ribbed piston bowl. At higher injection pressures, the redirection of fuel vapors from the in-line fuel jet back toward the ignition assistant (IA) increased the residence time the fuel mixture was exposed to the hot zone from the ignition assistant, reducing the possibility of misfires. Results also
Amezcua, Eri R.Stafford, Jacob M.Rothamer, David A.Kim, Kenneth S.Kweon, Chol-bum M.
Moisture adsorption and compression deformation behaviors of Semimet and Non-Asbestos Organic brake pads were studied and compared for the pads cured at 120, 180 and 240 0C. The 2 types of pads were very similar in moisture adsorption behavior despite significant differences in composition. After being subjected to humidity and repeated compression to 160 bars, they all deform via the poroviscoelastoplastic mechanism, become harder to compress, and do not fully recover the original thickness after the pressure is released for 24 hours. In the case of the Semimet pads, the highest deformation occurs with the 240 °C-cure pads. In the case of the NAO pads, the highest deformation occurs with the 120 0C-cure pads. In addition, the effect of pad cure temperatures and moisture adsorption on low-speed friction was investigated. As pad properties change all the time in storage and in service because of continuously changing humidity, brake temperature and pressure, one must question any
Rhee, Seong KwanRathee, AmanSingh, ShivrajSharma, Devendra
The automotive industry faces unprecedented regulatory and societal pressure to adopt sustainable manufacturing practices. A recent survey by Accenture shows that more than 34 percent of today’s largest manufacturers have committed to zero-emission goals, yet 93 percent of them will miss their targets unless they double their emission reduction rates by 2030
A new groundbreaking “smart glove” is capable of tracking the hand and finger movements of stroke victims during rehabilitation exercises. The glove incorporates a sophisticated network of highly sensitive sensor yarns and pressure sensors that are woven into a comfortable stretchy fabric, enabling it to track, capture, and wirelessly transmit even the smallest hand and finger movements
In recent decades, it can be noted an advance in new technologies applied to commercial vehicles. This advancement led to the development of new functions making products more efficient and safer, benefiting the society in general. Commercial vehicle manufacturers brought their products to levels higher than those required by current legal resolutions. Among the various resolutions applied to the braking system, in CONTRAN #915/22, which specifies minimum requirements of performance of vehicles brakes, the part 7 of NBR 10966 stands out. This standard determines requirements for compatibility between towing and towed units combined as a vehicle. The purpose of this study was to evaluate the thermal balance between the brakes of a motor vehicle combined with a semi-trailer. The tests were carried out by varying the pneumatic pressure that controls the service brake of towed units during braking. Some of the pressure levels were complying with compatibility requirements, others were not
Dias, Eduardo MirandaTravaglia, Carlos Abílio PassosRodrigues, AndréRudek, CludemirBritto, Danilo
There are examples in aerodynamics that take advantage of electric-to-aerodynamic analogies, like the law of Biot–Savart, which is used in aerodynamic theory to calculate the velocity induced by a vortex line. This article introduces an electric-to-aerodynamic analogy that models the lift, drag, and thrust of an airplane, a helicopter, a propeller, and a flapping bird. This model is intended to complement the recently published aerodynamic equation of state for lift, drag, and thrust of an engineered or a biological flyer by means of an analogy between this equation and Ohm’s law. This model, as well as the aerodynamic equation of state, are both intended to include the familiar and time-proven parameters of pressure, work, and energy, analytical tools that are ubiquitous in all fields of science but absent in an aerodynamicists’ day-to-day tasks. Illustrated by various examples, this modeling approach, as treated in this article, is limited to subsonic flight
Burgers, Phillip
Sustainability remains a dominant trend in packaging and processing, continuing to attract the attention of the life sciences industry and inspire its new initiatives. Although pharmaceutical and medical device manufacturers must prioritize patient safety and product protection, concerns about climate change, greenhouse gas (GHG) emissions, plastic waste, and pressure to move toward a circular economy are prompting a greater focus on improving the sustainability of their products and packaging
Membranes of vertically aligned carbon nanotubes (VaCNT) can be used to clean or desalinate water at high flow rate and low pressure. Recently, researchers of Karlsruhe Institute of Technology (KIT) and partners carried out steroid hormone adsorption experiments to study the interplay of forces in the small pores. They found that VaCNT of specific pore geometry and pore surface structure are suited for use as highly selective membranes. The research was published in Nature Communications
If an external force with changing amplitude acts on an elastic medium such as a gas, a liquid or a solid, an undulating propagation of pressure and density fluctuation occurs in space and time, starting from the point where the force is applied. This is known as sound. The frequency of sound waves ranges from a few hertz (Hz) up to several gigahertz (see Figure 1). Infrasound, the sound humans cannot hear, lies at frequencies below 16 Hz. It is followed by the hearing range, which reaches up to 20 kHz. Ultrasonic waves, which cannot be heard, lie in the frequency range from 20 kHz to 1.6 GHz, which equals 16 billion cycles per second. A prominent application example in medical technology is the use of ultrasound for diagnostic imaging techniques. In industry and research, ultrasound is mainly used in measurement technology, where sound waves with low power are used. The intensity of the sound describes the power that hits a certain surface. If it exceeds 10 W/cm2, we speak of power
Tank Technologies, a company producing porcelain-lined water heaters, faced significant challenges with their manual cutting processes. Challenges in the cutting process are detrimental in an industrial landscape where speed requirements and cost pressures are high. The introduction of Hirebotics’ Cobot Cutter significantly improved their operations, drastically reducing rework, improving cycle times, and elevating overall efficiency
Continental's Georg Fässler, executive chair of the 2024 SAE COMVEC, details efforts to future-proof forthcoming vehicles. Severe driver shortages, rising fuel and material costs, escalating demand for freight transport, higher sustainability requirements - there is no shortage of challenges facing the transport sector. Commercial vehicle manufacturers and industry suppliers are devoting significant resources to develop, test and bring to market the technological advances that will help alleviate these pressure points. “The digitalization of commercial vehicles and the whole logistics chain is a necessary response and one of the most important developments in the CV industry in my view,” said Continental Automotive's head of commercial and special vehicles, Georg Fässler, in a recent interview with SAE International
Gehm, RyanUhrinek, Gretchen
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