Improving aircraft cabin air quality by reducing tri-cresylic phosphate

Bleed air ECS extract air from engine compressor and is subject to increase the toxic chemicals in the cabin air. One of the most harmful of them is Tri-Cresylic Phosphate (TCP). It is a common anti-wear additive used in jet engine oils and exposure to this chemical increases the risks of various adverse health effects. Additionally, the European Aviation Safety Agency (EASA) which implements and monitors safety issues in aircrafts has yet to come up with an exposure limit for TCP’s. The effect of TCP and its filtration is analyzed and showed that by means of Carbon Active filters can be reduced

More frequent flight in the ash polluted sky using electrostatic filter

Thousands of flights were banned and millions of people have affected in Europe in 2010. This was the first natural event which caused a wide and long flight ban in the world, the biggest shut down after Second World War. The damage in European countries is estimated as figure as billions of Dollars and in particular, a damage of 10 million Pounds a day was estimated for Britain. Because of the volcanic event and its development, aviation authorities of European countries decided to restrict the use of airspace, progressively as the ash cloud was spreading. From April 15th to May 21st were restricted airspace, airports were closed, flights canceled and passengers repressed, so it became the longest period of inactivity in air traffic after the Second World War. International Air Transport Association (IATA) estimated losses of 1.1 billion pounds, affecting 1.2 million passengers per day which accounted for 29% of world aviation. The Airport Operators Association (AOA) estimated losses of 80 million pounds in six days and a half, for a total of 100,000 flights canceled. Volcanic eruptions are different each one, as to which its style determines the chemistry, physical and chemical components, and particle size of volcanic ash. During an eruption, the lava can flow slowly like a thick liquid (Effusive) or may be accompanied by ash and gases (Explosive).Explosive eruptions pose the greatest risk to aviation because they are always accompanied by ash production. Shafil system is in the process of design and integration to mitigate the intake ash into aircraft engine. It generates a negative electric field to ionize gas around, so that the dust particles receive the negative charge then be carried to a surface with an opposite polarity, and eventually be collected for packing

Vortex generator effect on mitigation of separation in transonic flow nozzle

The effect of tetrahedral sub-boundary layer vortex generator on plummeting normal shock-induced turbulent boundary layer separation has been investigated in computational environment and the result is presented. A good agreement achieved in this work between the pre-assessed experimental and current CFD results, opens the way for further utilization of CFD in the area of shock/boundary layer interaction with 3-D mean compressible flow field, particularly for complicated geometries. The outcome style sheet is illustrated by the portions given in this document

Computational simulated verification of hybrid laminar flow design by suction method

Rise in the performance and therefore profit of airliners is a major challenge for aircraft designers. Here, the design of a Hybrid Laminar Flow Control system is considered and a computational verification has been done to show the performance of the system and by employing the fundamental equations, it showed that the required level of suction across a wing to efficiently suppress flow is achievable. A novel system was designed that could be incorporated into the leading edge of large civil aircraft or adapted to suit alternative aircraft using a combination of active and passive suction methods. A turbo compressor has been employed to provide the certain level of suction, whereas the passive system automatically produces suction by introducing ducting from the high pressure region at the leading edge to the low pressure region at the underside of the wing. By this method the fuel saving of 5% is achievable. The outcome of the investigation shows a good meeting with computational analysis and the available source of validation. This method is recommended to be experimentally investigated

Formation flight investigation for highly efficient future civil transport aircraft

Formation flight could greatly assist the air transport industry in tackling the challenges of environmental impact, excessive reliance on fuel and overcapacity. Previous studies have shown drag reductions leading to significant fuel savings for aircraft in formation relative to their solo flight. Safety is guaranteed with the use of extended formation distances, and practical implementation issues could be solved in the near future. Since studies so far have focused on existing aircraft configurations and technology, a case study using a strut-braced wing airliner was carried out to ascertain its applicability to less conventional craft. The present results did not indicate such clear-cut benefits. If formation flight is to be successful and beneficial for the next generations of aircraft, it will be vital to consider its interaction with new technologies developed for highly efficient operation, in particular those aimed at reduction of aircraft drag such as laminar flow, and to do so early in the design of aerospace vehicles and wider systems

Enriched air quality for aircraft electrical environmental control system with high pressure water separator

The Electrical Environmental Control System (EECS) uses separate compressor and electric motor for compressed air instead of air extracting bleed air from engine. For a civilian aircraft carrying 200 passengers with temperature of 22 ℃, Relative Humidity (RH) of 15-18% and cruise altitude of 35,000 feet, the EECS is equipped with two independently electronically controlled three-wheel bootstrap Air Cooling Machine packs with high pressure water separator which are capable of supplying enough amount of fresh ventilation air of 1.3kg/s as per the design requirements. Cabin pressurisation systems are incorporated to maintain average cabin altitude of 5500 and not more than 7000ft. Air from the atmosphere is drawn by compressor operated by electronically controlled electrical motor. Before the air entering the main compressor, an inertial high pressure water separator is provided to separate the water or excess moisture. Water separator is by-passed once the aircraft attains higher altitude to avoid complete removal of moisture from air. The process promises a higher air quality for passengers and crew

Compound actuation system design for an advanced space transportation reusable orbiter

The SL-12 is a reusable space orbiter which offers the capability to go beyond the notion of a second generation space shuttle, and is targeted to be in operation in the year 2020. SL-12 Orbiter utilizes gimballing of the main rocket engines for control during ascent and typical aerodynamic surfaces for control during re-entry, approach, and landing. Power by wire (PBW) Actuation system is used for SL-12 based on All Electric Aircraft (AEA) approach. Electro Hydrostatic Actuators have been used for Primary Flight Control surfaces (Elevon, Body Flap and Rudder) and Thrust Vector Control for Main Engine Module, Electro Mechanical actuators have been used for Thrust Vector Control of Orbital Maneuvering System and Payload bay door. Dual redundant electric power supply channels are used for redundancy. Actuation System Safety and Reliability analysis has been done to ensure compliance and specification requirements

Simulating actuator energy consumption for trajectory optimisation

This work aims to construct a high-speed simulation tool which is used to quantify the dynamic actuator power consumption of an aircraft in flight, for use within trajectory optimisation packages. The purpose is to evaluate the energy penalties of the flight control actuation system as an aircraft manoeuvre along any arbitrary trajectory. The advantage is that the approximations include major transient properties which previous steady state techniques could not capture. The output can be used to provide feedback to a trajectory optimisation process to help it compute the aircraft level optimality of any given flight path. The tool features a six degree of freedom dynamic model of an aircraft which is combined with low frequency functional electro-mechanical actuator models in order to estimate the major transient power demands. The actuator models interact with the aircraft using an aerodynamic load estimator which generates load forces on the actuators that vary as a function of flight condition and control surface demands. A total energy control system is applied for longitudinal control and a total heading control system is implemented to manage the lateral motion. The outer loop is closed using a simple waypoint following guidance system with turn anticipation and variable turn radius control. To test the model, a simple trajectory analysis is undertaken which quantifies a heading change executed with four different turn rates. The tool shows that the actuation system requires 12.8 times more electrical energy when performing a 90° turn with a radius of 400 m compared to 1000 m. A second test is performed to verify the model’s ability to track a longer trajectory under windy conditions

Simulation for temperature control of a military aircraft cockpit to avoid pilot’s thermal stress

During flying, military pilots are normally subjected to a number of stresses like mild hypoxia, high accelerations, vibrations and thermal discomfort. Among all of these, thermal stress is the most predominant factor while operating in highly tropical regions. Despite the use of aircraft’s environmental control system, the temperature inside the cockpit may easily reach more than 10 °C above ambient temperature and sometimes it may even exceed 45 °C. When these extreme temperatures are coupled with high relative humidity, causes for the degradation of both mental and physical performance of the pilots are present. This situation becomes severe, especially during low altitude and high-speed operations due to aerodynamic heating of the external surfaces. Sometimes, at high altitude and low-speed operations, the cockpit temperature falls and cold stress can pose a serious problem on the health of pilots. It is necessary to protect the pilots from high thermal stress to keep them under safe thermoregulatory limits and also help them perform an intended mission. This paper develops and deploys a basic method that can be used at an early design stage of any military aircraft to analyse the environmental control system’s performance in avoiding pilot thermal stress. The method is also applicable to a design study for an enhanced environmental control system on an existing aircraft. Results present the effect of parameters including Mach number, altitude, ambient temperature, cockpit geometry, and solar radiation on cockpit thermal balance which have a direct impact on the thermal stress on pilots. A military aircraft with a cockpit volume of 1.5 m3 is considered for performing the thermal balance simulation studies. This paper also addresses the effects on engine bleed flow requirements, and corresponding air inlet temperatures to maintain the cockpit target wet bulb globe temperature of 28 °C as well as a pilot mean skin temperature target of 33 °C. These are some of the thermal stress indicators proposed by different aero-medical authorities. These requirements are to be maintained if the physiological stress and impairment of performance of the pilots are to be avoided while operating in hot and humid environment

In vitro Cytotoxic Activity of Four Plants Used in Persian Traditional Medicine

Purpose: The aim of this study was to investigate in vitro cytotoxic activity of four methanolic crude plant extracts against panel cell lines. Methods: Methanolic extracts were tested for their possible antitumor activity and cytotoxicity using the 3-(4,5-dimetylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay on six cancer cell lines; non-Hodgkin’s B-cell lymphoma (Raji), human leukemic monocyte lymphoma (U937), human acute myelocytic leukemia (KG-1A), human breast carcinoma (MCF-7 cells), human Prostate Cancer (PC3) and mouse fibrosarcoma (WEHI-164) cell lines and one normal cell line; Human Umbilical Vein Endothelial Cells (HUVEC). Results: All species showed dose dependent inhibition of cell proliferation. IC50 values ranging from 25.66±1.2 to 205.11±1.3 μg/ml. The highest cytotoxic activity Chelidonium majus L> Ferulago Angulata DC> Echinophora platyloba DC> Salvia officinalis L, respectively. Conclusion: all extracts demonstrate promising cytotoxicity activity as a natural resource for future bio-guided fractionation and isolation of potential antitumor agents