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Analytical and Experimental Study on Complex compressed air Pipe Network

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Chinese Journal of Mechanical Engineering 2015年第5期28卷 1023-1029页

作者： GAI Yushou CAI Maolin SHI Yan School of Automation Science and Electrical Engineering Beihang University

To analyze the working characteristics of complex compressed air networks, numerical methods are widely used which are based on finite element technology or intelligent algorithms. However, the effectiveness of the numerical methods is limited. In this paper, to provide a new method to optimize the design and the air supply strategy of the complex compressed air pipe network, firstly, a novel method to analyze the topology structure of the compressed air flow in the pipe network is initially proposed. A matrix is used to describe the topology structure of the compressed air flow. Moreover, based on the analysis of the pressure loss of the pipe network, the relationship between the pressure and the flow of the compressed air is derived, and a prediction method of pressure fluctuation and air flow in a segment in a complex pipe network is proposed. Finally, to inspect the effectiveness of the method, an experiment with a complex network is designed. The pressure and the flow of airflow in the network are measured and studied. The results of the study show that, the predicted results with the proposed method have a good consistency with the experimental results, and that verifies the air flow prediction method of the complex pipe network. This research proposes a new method to analyze the compressed air network and a prediction method of pressure fluctuation and air flow in a segment, which can predicate the fluctuation of the pressure according to the flow of compressed air, and predicate the fluctuation of the flow according to the pressure in a segment of a complex pipe network.

关键词： compressed air pipeline network topology structure flow prediction topology

compressed air System Optimization Techniques and Applications Study

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Compressed Air System Optimization Techniques and Applicatio...

第五届压缩机与制冷国际会议

作者： Hongbo Qin Shougen HuUniversity of Shanghai for Science and TechnologyHongbo QinShanghai Energy Conversation Service Center

＜正＞ compressed air system and life cycle analysis are introduced at first. Some key system energy saving opportunities and techniques, such as eliminating inappropriate uses, minimizing leaks and pressure drop, stabilizing system supply pressure, optimizing system configuration, optimizing control system with multiple compressors and engineering controlled air storage are analyzed. Some typical successful case study of China Motor System Energy Program, supported by United National Industrial Development Organization, is also briefly introduced along these techniques.Due to cleanness, readily-availability, and simple-to-use, compressed air is used widely throughout industry, such as pneumatic tools, pneumatic controls, compressed air operated cylinders for machine actuation, product cleansing, and blow-offs, and is often considered the "fourth utility" at many facilities. But compressed air is probably the most expensive form of energy available in a plant, because only 19% of the power used by a compressor can be convened to useable work, and the other 81% is lost as waste heat . This is a theoretical calculation because other system losses are not taken into account. With increased worldwide energy costs and electricity shortage in China in recent years, manufacturers are realizing that compressed air is not free and beginning to looking for the methods to reduce the energy consumption of compressed air system.

关键词： compressed air Optimization

compressed air System Performance Measurement and Analysis Method Study

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Compressed Air System Performance Measurement and Analysis M...

第五届压缩机与制冷国际会议

作者： Wayne Perry Kaeser compressors Inc.

＜正＞ compressed air system performance measurement methods, including pressure at key positions of system, system flow rate and power to develop system pressure profile, demand profile and compressor power profile, are studied and compared. Based on the pressure profile, demand profile and compressor power profile developed according to collected data by data logger, analysis method to identify high volume intermittent demand events, perceived high pressure demands and overall system performance is also introduced.compressed air is used widely throughout industry and is often considered the "fourth utility" at many facilities. Almost every industrial plant, from a small machine shop to an immense pulp and paper mill, has some type of compressed air system. Compared with equipment initial investment and maintenance, electricity consumption to operate compressors usually represents more than 75% of overall cost of compressed air. Improving and maintaining peak compressed air system performance requires not only addressing individual components, but also analyzing both the supply and demand sides of the system and how they interact. System approach should be applied to measure and analyze the performance of overall compressed air system, which usually involves the following types of interrelated actions: analyzing compressed air needs, system measurement to develop operation profiles and analyzing operating data and identifying potential improvement opportunities.

关键词： compressed air measurement methods

Modern Hyperbaric, Safety ＆ Medical Management of llinnelling Operations ＆ TBM Intervention in compressed air

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Modern Hyperbaric, Safety ＆ Medical Management of llinnelli...

大直径隧道与城市轨道交通工程技术——2005上海国际隧...

作者： A.R.RIDLEY Tony Ridley Hyperbaric Associates Limited Norwich Norfolk.UK

＜正＞This paper has looked at the key areas of Modern Hyperbaric, Safety ＆ Medical Management of Tunnelling Operations ＆ TBM Intervention in compressed air from the viewpoint and associated operational experience of the authors. Only those totally unfamiliar with modern hyperbaric tunnelling techniques and health surveillance, can now dispute that the whole interactive spectrum of required cover is very complex and requires expert management and execution.

关键词： health safety management hyperbaric management compressed air

Train model acceleration and deceleration

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Science China Technological Sciences 2013年第3期56卷 642-647页

作者： YANG QianSuo SONG JunHao LI Duo ZHANG Jie YANG GuoWei State Key Laboratory of High Temperature Gas Dynamics Institute of MechanicsChinese Academy of Sciences

In order to accelerate a heavy train model with great dimensions to a speed higher than 300 km h?1 in a moving train model testing system,compressed air is utilized to drive the train model indirectly.The gas from an air gun pushes the piston in an accelerating tube forward.The piston is connected to the trailer through a rope,and the trailer pulls the train model to the desired speed.After the testing section,the train model enters the deceleration section.The speed of the train model gradually decreases because of the braking force of the magnetic braking device on the bottom of the train model and the steel plates fixed on the floor of this device.The dissipation of kinetic energy of the trailer is also based on a similar principle.The feasibility of these methods has been examined in a 180 m-long moving train model testing system.The speed of the trailer alone reaches up to 490 km h-1.Consequently,a 34.8 kg model accelerates up to 350 km h?1;the smooth and safe stopping of the model is also possible.

关键词： moving train model acceleration deceleration magnetic braking air gun compressed air

Rectosigmoid perforation after high-pressure air jet exposure: A case report

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Journal of Acute Disease 2020年第6期9卷 272-274页

作者： Suman Rastogi Anandhi Devendiran Divankur Khanna Nanda Kishore Maroju KNJPrakash Raju Department of Emergency Medicine&Trauma Jawaharlal Institute of Postgraduate Medical Education and Research(JIPMER)PuducherryIndia Department of Surgery Jawaharlal Institute of Postgraduate Medical Education and Research(JIPMER)PuducherryIndia

Rationale:Colonic barotrauma induced by high-pressure air compressors has been reported more frequently these days due to the widespread use of air compressors in industries.Such enormous pressure into the rectum can lead to devastating injuries.Patient's concern:A 35-year-old male was referred to our emergency department with an alleged history of directing high pressure compressed air jet towards the anus.There was diffuse subcutaneous emphysema over the neck,chest,abdomen,and extremities,and he presented with hemodynamic instability and respiratory failure.Diagnosis:Rectosigmoid perforation due to exposure to high-pressure air jet causing tension pneumoperitoneum,pneumomediastinum,pneumothorax,and extensive subcutaneous emphysema.Intervention:In view of tension pneumoperitoneum,urgent percutaneous needle decompression was performed using 16 G needle,5 cm superomedial to the anterior superior iliac spine.The gush of air was released along with reduction in abdominal distension and improvement in hemodynamics.Outcome:The patient succumbed two days later due to septic shock.Lessons:This case highlighted the importance of promoting education about work safety among industrial workers especially in developing countries like India.

关键词： compressed air Ruptured colon Colonic barotraumas Mediastinal emphysema

Mountain Atmospherics

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Natural Science 2021年第6期13卷 208-210页

作者： Kern E. Kenyon 4632 North Lane Del Mar CA USA

The purpose of the work is to examine the effects of compressibility on air properties when a wind blows against a sloping mountain surface. Previous research of air compression effects include the low speed wing and the crests of surface gravity waves propagating in the wind. In both cases, an algebraic expression was obtained for the lift force. When wind blows across a mountain and the assumption is made that a boundary layer of compressed air forms and remains attached to the mountain, a physical-chemical theory predicts that the wind will have no shear and the pressure and density will decrease with increasing altitude at the same rate. Combining Bernoulli’s law along streamlines with the cross-stream force balance, pressure gradient equals centrifugal force, and the perfect gas law for air, is the model used here.

关键词： Mountain Winds compressed air Upward Decreases of Pressure and Density

A study on dysbaric osteonecrosis in caisson workers

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A study on dysbaric osteonecrosis in caisson workers

第十三次全国劳动卫生与职业病学术会议

作者：匡兴亚

PURPOSE:To study the effects of exposure to compressed air on tunnel workers’health and to investigate the prevalence of dysbaric osteonecrosis(DON)in caisson workers.METHODS:128 tunnel workers were divided into the exposed group(n=58)and the control group(n=70),and their shoulders,hips and knees were examined with X-ray,CT and MRI.RESULTS:①34.5%of the exposed group were diagnosed with DON based on the national diagnostic criteria of decompressed sickness.②The incidental difference of skeletal cystic changes between the exposed group and the control group was highly statistically significant(p<0.01).③CT and MRI examination could detect early onset of DON lesions,and the cystic changes shown in CT and abnormal signals in MRI were diagnostic indicators in cases.CONCLUSION:Cystic changes in CT and abnormal signals in MRI are key imaging findings of early DON.

关键词： tunnel workers caisson workers compressed air decompression sickness dysbaric osteonecrosis（DON）