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Aircraft cabin pressurization system
- 1. TE SEMINARPRESENTATION ON “AIRCRAFT CABINPRESSURIZATION SYSTEM” By Mr.ShrinivasKale UndertheGuidanceof Prof.Mrs.PallaviGhogare Department of Mechanical Engineering, PES’s MODERN COLLEGE OF ENGINEERING, PUNE
- 2. SUMMARY LITERATURE REVIEW INTRO:FOOT DROP CAUSES EXISTING DEVICES PROBLEM FORMULATION SUMMARY : •Introduction • Literature Review • Problem Formulation • Objectives • Methodology • Hypothesis • Work Plan • References
- 3. SUMMARY LITERATURE REVIEW INTRO:FOOT DROP CAUSES EXISTING DEVICES PROBLEM FORMULATION INTRODUCTION : Cabin pressurizationis a process in which conditioned air is pumped into the cabin of an aircraft or spacecraft, in order to create a safe and comfortable environment for passengers and crew flying at high altitudes. For aircraft, this air is usually bled off from the gas turbine engines at the compressor stage, and for spacecraft, it is carried in high-pressure, often cryogenic tanks. The air is cooled, humidified, and mixed with recirculated air if necessary, before it is distributed to the cabin by one or more environmental control systems. The cabin pressure is regulated by the outflow valve.
- 4. SUMMARY LITERATURE REVIEW INTRO:FOOT DROP CAUSES EXISTING DEVICES PROBLEM FORMULATIO N Sr. No. Title of Paper Author andYear of Publication Summary 1 High altitude airship cabin sizing, pressurization and air conditioning Antonio Dumas, Diego Angeli, Michele Trancossi This paper aims at defining a design methodology for the global thermodynamic performance of a high altitude airship cabin. This design method applies to different systems, which could not use the traditional air conditioning plant layout based on bleed air intake from the compressor stage of jet engines. 2 Evaluation of an improved air distribution system for aircraft cabin Liping Pang, Jie Xu, Lei Fang, Mengmeng Gong, Hua Zhang, Yu Zhang An improved air distribution system for aircraft cabin was proposed in this paper. Personalized outlets were introduced and placed at the bottom of the baggage hold. 3 A novel environmental control system facilitating humidification for commercial aircraft Long Chen, Xingjuan Zhang, Chao Wang, Chunxin Yang A new integrated system featuring air supply, pressure regulation, temperature control, water separation, and cabin humidification is proposed based on numerous field investigations, existing cabin humidification methods, and conventional aircraft environmental control systems. LITERATURE REVIEW :
- 5. SUMMARY LITERATURE REVIEW INTRO:FOOT DROP CAUSES EXISTING DEVICES PROBLEM FORMULATIO N Sr. No. Title of Paper Author and Yearof Publication Summary 4 The appropriate airflow rate for a nozzle in commercial aircraft cabins based on thermal comfort experiments Xiuyuan Du, Baizhan Li, Hong Liu, Yuxin Wu, Tengfei Cheng To study the effect of the nozzle air supply on thermal comfort and optimize the airflow rate for a nozzle, both measurements of the air flow field and a human thermal comfort survey were carried out in and experimental three-row aircraft cabin. The experiments used four airflow rates (0 L/s, 0.67 L/s, 0.96 L/s and 1.45 L/s) for a nozzle and three different cabin temperatures (24°C, 26°C, 28°C). The air velocity distribution was obtained to calculate the air velocity for the nozzle jets at any point. 5 High altitude airship cabin sizing, pressurization and air conditioning Antonio Dumas, Diego Angeli, Michele Trancossi This paper aims at defining a design methodology for the global thermodynamic performance of a high altitude airship cabin. This design method applies to different systems, which could not use the traditional air conditioning plant layout based on bleed air intake from the compressor stage of jet engines. 6 Evaluation of an improved air distribution system for aircraft cabin Liping Pang, Jie Xu, Lei Fang, Mengmeng Gong, Hua Zhang, Yu Zhang An improved air distribution system for aircraft cabin was proposed in this paper. Personalized outlets were introduced and placed at the bottom of the baggage hold. Its ratio of fresh air to recirculation air and the conditioned temperature of different types of inlets were also designed carefully to meet the goals of high air quality, thermal comfort and energy saving.
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- 7. OBJECTIVES METHODOLOG Y HYPOTHESI S WORKPLAN END! 21 OBJECTIVES : The overallpurpose of copyright law is to prevent unfair competition by protecting the use of a symbol, word, logo, slogan, design, domain name, etc. that uniquely distinguishes the goods or services of a firm, Patents, Trademarks, and Copyrights" To do a case study on a patented Aircraft Cabin Pressurization System by analysing its constructional details and performance parameters. Then finally deducing its advantages and disadvantages.
- 8. OBJECTIVES METHODOLOG Y HYPOTHESI S WORKPLAN END! METHODOLOGY : Aim:New system required for cabin air pressurization Background information: Old system are not efficient Idea Overview: Cabin Air Pressurization with reference to Aircraft Idea Overview: Cabin Air Pressurization with reference to Aircraft Claims : Developing new Aircraft Cabin Pressurization System
- 9. NEED FOR CABINPRESSURIZATION : Pressurization becomes increasingly necessary at altitudes above 10,000 feet (3,000 m) above sea level to protect crew and passengers from the risk of a number of physiological problems caused by the low outside air pressure above that altitude. For private aircraft operating in the US, crew members are required to use oxygen masks if the cabin altitude stays above 12,500 ft for more than 30 minutes, or if the cabin altitude reaches 14,000 ft at any time. At altitudes above 15,000 ft, passengers are required to be provided oxygen masks as well. On commercial aircraft, the cabin altitude must be maintained at 8,000 feet (2,400 m) or less. Pressurization of the cargo hold is also required to prevent damage to pressure-sensitive goods that might leak, expand, burst or be crushed on re-pressurization.
- 10. PHYSIOLOGICAL PROBLEMS ARISINGDUE TO FAILURE OF CABIN PRESSURIZATION: Hypoxia : The lower partial pressure of oxygen at altitude reduces the alveolar oxygen tension in the lungs and subsequently in the brain, leading to sluggish thinking, dimmed vision, loss of consciousness, and ultimately death. Altitude sickness :Hyperventilation, the body's most common response to hypoxia, does help to partially restore the partial pressure of oxygen in the blood, but it also causes carbon dioxide (CO2) to out-gas, raising the blood pH and inducing alkalosis. Decompression sickness : The low partial pressure of gases, principally nitrogen (N2) but including all other gases, may cause dissolved gases in the bloodstream to precipitate out, resulting in gas embolism, or bubbles in the bloodstream. Barotrauma : As the aircraft climbs or descends, passengers may experience discomfort or acute pain as gases trapped within their bodies expand or contract.
- 11. BASIC SYSTEM OPERATION: Pressurization is achieved by the design of an airtight fuselage engineered to be pressurized with a source of compressed air and controlled by an environmental control system (ECS). The most common source of compressed air for pressurization is bleed air extracted from the compressor stage of a gas turbine engine, from a low or intermediate stage and also from an additional high stage; the exact stage can vary depending on engine type. By the time the cold outside air has reached the bleed air valves, it is at a very high pressure and has been heated to around 200 °C (392 °F). The control and selection of high or low bleed sources is fully automatic and is governed by the needs of various pneumatic systems at various stages of flight. The part of the bleed air that is directed to the ECS is then expanded to bring it to cabin pressure, which cools it. A final, suitable temperature is then achieved by adding back heat from the hot compressed air via a heat exchanger and air cycle machine known as the packs system. In some larger airliners, hot trim air can be added downstream of air conditioned air coming from the packs if it is needed to warm a section of the cabin that is colder than others.
- 12. At leasttwo engines provide compressed bleed air for all the plane's pneumatic systems, to provide full redundancy. Compressed air is also obtained from the auxiliary power unit (APU), if fitted, in the event of an emergency and for cabin air supply on the ground before the main engines are started. Most modern commercial aircraft today have fully redundant, duplicated electronic controllers for maintaining pressurization along with a manual back-up control system. All exhaust air is dumped to atmosphere via an outflow valve, usually at the rear of the fuselage. This valve controls the cabin pressure and also acts as a safety relief valve, in addition to other safety relief valves. If the automatic pressure controllers fail, the pilot can manually control the cabin pressure valve, according to the backup emergency procedure checklist. The automatic controller normally maintains the proper cabin pressure altitude by constantly adjusting the outflow valve position so that the cabin altitude is as low as practical without exceeding the maximum pressure differential limit on the fuselage. The pressure differential varies between aircraft types, typical values are between 7.8 psi (54 kPa) and 9.4 psi (65 kPa). At 39,000 feet (12,000 m), the cabin pressure would be automatically maintained at about 6,900 feet (2,100 m) (450 feet (140 m) lower than Mexico City), which is about 11.5 psi (79 kPa) of atmosphere pressure.
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- 14. NEW CABIN PRESSURIZATIONSYSTEM : A system for controlling cabin pressurization in an aircraft cabin, comprising: First means for providing a cabin altitude signal indicative of the air pressure in said aircraft cabin. Second means for providing a cabin altitude rate change signal indicative of the actual rate of change of air pressure in said aircraft cabin. Third means for providing an aircraft altitude signal indicative of the ambient air pressure on the exterior of the aircraft, and hence the altitude of the aircraft; Auto schedule means for calculating a commanded rate of change of air pressure in said aircraft cabin in response to aircraft altitude. Means for controlling the air pressure in said aircraft cabin in response to said cabin altitude signal and said commanded rate of change. Clamp control means for maintaining a constant pressure situation in said aircraft cabin, said constant pressure situation being initiated when the change of said aircraft altitude signal over a preset time period is less than a first predetermined value, said constant pressure situation being maintained until said aircraft altitude signal changes by a second predetermined value from the value of said aircraft altitude signal at the time said constant pressure situation was initiated.
- 15. ADVANTAGES : This Systemhelps to maintain Aircraft cabin pressure at high altitude with great precision and accuracy. It respond to minor changes in cabin pressure with respect to aircraft altitude. It generates ambient atmosphere for passengers and prevents passengers from physiological problems. It also maintains and monitor cabin air quality as per directed by WHO.
- 16. CONCLUSION : The Conclusionof this case study is that the Aircraft Pressurization System is very much precise and accurate. Aircraft Pressurization System is easy to handle and it must be regularly and precisely maintained by well trained engineers.
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