scholarly journals Calculation of the total cross-sectional area of the spool air of the distributor of an automobile air motor

2019 ◽  
Keyword(s):  
Distribution System ◽  
Combustion Engine ◽  
Slide Valve ◽  
Compressed Air ◽  
Entry And Exit ◽  
Flow Area ◽  
Cross Sectional ◽  
Software Application ◽  
Analytical Estimation ◽  
Separate Block

One of actual issues in the field of gas dynamics of piston engines which concerns the analytical estimation of influence of structural and regime parameters on the processes of flowing of gases through gas distribution mechanisms is examined. Gas interchange process in two-tact engines is performed by means of opening-closing of blow-off windows or slide-valve with a piston. The method of calculating the total plane of the flow area of slide-valve air distributor for a motor-car pneumatic engine is proposed. The mathematical descriptions of the pre-set areas of the entry and exit openings of slide-valve air distributor have been performed with the help of the theory of R-functions. The algorithm for creating the computer calculating program for determining the flow area of slide-valve air distributor is considered. The proposed algorithm has been used for developing the software application intended for calculating the areas which are formed by the entry and exit openings of slide-valve accounting for their different possible configurations. The calculations of flow area of these openings allow determining the air losses in the air distributive system of pneumatic engine and defining the specific size for the inlets and outlets of the compressed air. The results of calculations of the air distribution system and the parameters of the compressed air intake is presented as a separate block in the general dynamic model of calculations of working processes of the motor-car pneumatic engine, when determining the speed, temperature and air flow of the slide-valve air distributor. The motor-car pneumatic engine is more economical and environmentally friendly in comparison with the internal combustion engine at the low revolutions.

scholarly journals Cold bubble humidification of low-flow oxygen does not prevent acute changes in inflammation and oxidative stress at nasal mucosa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lauriana Alves Santana ◽  
Suellen Karoline Moreira Bezerra ◽  
Beatriz Mangueira Saraiva-Romanholo ◽  
Wellington Pereira Yamaguti ◽  
Iolanda de Fátima Lopes Calvo Tibério ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nasal Mucosa ◽  
Oxygen Therapy ◽  
Mucociliary Clearance ◽  
Nasal Cannula ◽  
Compressed Air ◽  
Low Flow ◽  
Cross Sectional ◽  
Nasal Symptoms ◽  
Nasal Inflammation

AbstractSome clinical situations require the use of oxygen therapy for a few hours without hypoxemia. However, there are no literature reports on the effects of acute oxygen therapy on the nasal mucosa. This study aimed to evaluate the acute effects of cold bubble humidification or dry oxygen on nasal Inflammation, oxidative stress, mucociliary clearance, and nasal symptoms. This is a randomized controlled cross-sectional study in which healthy subjects were randomly allocated into four groups: (1) CA + DRY (n = 8): individuals receiving dry compressed air; (2) OX + DRY (n = 8): individuals receiving dry oxygen therapy; (3) CA + HUMID (n = 7): individuals receiving cold bubbled humidified compressed air; (4) OX + HUMID (n = 8): individuals receiving cold bubbled humidified oxygen therapy. All groups received 3 L per minute (LPM) of the oxygen or compressed air for 1 h and were evaluated: total and differential cells in the nasal lavage fluid (NLF), exhaled nitric oxide (eNO), 8-iso-PGF2α levels, saccharin transit test, nasal symptoms, and humidity of nasal cannula and mucosa. Cold bubble humidification is not able to reduced nasal inflammation, eNO, oxidative stress, mucociliary clearance, and nasal mucosa moisture. However, subjects report improvement of nasal dryness symptoms (P < 0.05). In the conclusion, cold bubble humidification of low flow oxygen therapy via a nasal cannula did not produce any effect on the nasal mucosa and did not attenuate the oxidative stress caused by oxygen. However, it was able to improve nasal symptoms arising from the use of oxygen therapy.

The Use of Short-Term Compressed Air Supercharging in a Combustion Engine with Spark Ignition

2021 ◽  
Vol 18 (2) ◽  
pp. 8704-8713
Author(s):  
Jarosław Janusz Mamala ◽  
K. Praznowski ◽  
S. Kołodziej ◽  
G. Ligus
Keyword(s):  
Driving Force ◽  
Negative Impact ◽  
Combustion Engine ◽  
Spark Ignition ◽  
Compressed Air ◽  
Acceleration Process ◽  
Combustion Engines ◽  
Short Term ◽  
Drive Unit ◽  
The People

The powertrain is a very important subassembly in a car and is responsible not only for the automotive industry’s impact on the environment but also for the safety of people travelling by car and performing overtaking manoeuvres and joining traffic. In general, the powertrain is a combination of the drive unit and drive transmission, wherein the drive unit is responsible for the available driving force in the car’s wheels and for the car’s ability to accelerate when the throttle pedal is rapidly pressed at a constant gearbox ratio. The availability of the driving force reserve in the powertrain is the most important issue for the reason of safety of the people travelling by car. In the case of drive unit what they are of the combustion engines, the rapid pressing of the throttle pedal in the car acceleration process leads to a temporary deficiency in the driving force and in the powertrain’s output. The deficiency in the driving force has a negative impact on acceleration and driving comfort. In this paper, the authors assessed and analysed two different short-term compressed air supercharging systems for combustion engines with air supplied from a high-pressure tank. The analysis covered the response of the combustion engine with spark ignition to the gradual increase in pressure in the air-intake system. The assumption is that the applied short-term compressed air supercharging system could improve the driving force during the phase of the engine’s increasing crankshaft rotational speed. This helps to achieve the improved passenger car acceleration dynamics, depending on the supercharging method and throttle pedal exertion. When analysing the car’s acceleration dynamics, expressed by the shorter time of increasing the longitudinal speed from initial to final, it was possible to shorten the acceleration time. It is also possible to observe an improved driving force behaviour, especially during the first phase of acceleration.

scholarly journals Measurement of Permeability in Horizontal Direction of Open-Graded Friction Course with Rutting

2020 ◽  
Vol 12 (16) ◽  
pp. 6428
Author(s):  
Jaewon Yoo ◽  
Tan Hung Nguyen ◽  
Eungu Lee ◽  
Yunje Lee ◽  
Jaehun Ahn
Keyword(s):  
Hydraulic Gradient ◽  
Testing Equipment ◽  
Horizontal Direction ◽  
Flow Area ◽  
Cross Sectional ◽  
Traffic Loading ◽  
Test Methodology ◽  
Discharge Velocity ◽  
Open Graded Friction Course ◽  
Horizontal Permeability

Although the permeability of open-graded friction course (OGFC) materials in the transverse direction and the reduction in permeability associated with long-term traffic loading are important issues, they have remained under researched thus far. In this study, testing equipment and procedure were developed to evaluate the permeability of an OGFC specimen along the horizontal direction and its reduction due to rutting. Horizontal permeability tests were conducted by varying the hydraulic gradient of specimens with porosities of 19.6%, 15.6%, and 10.3%. The reduction in cross-section due to traffic loading was simulated via a wheel tracking test, and the permeability was subsequently evaluated. The reliability of test methodology was successfully verified; the tendency of the relationship between discharge velocity and hydraulic gradient was in good agreement with existing research results. The reduction in cross-sectional flow area due to rutting decreased and the horizontal permeability. The test results using developed testing equipment will enable efficient OGFC design.

scholarly journals Discharge Estimation Using Tsallis and Shannon Entropy Theory in Natural Channels

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1786
Author(s):  
Jitendra Kumar Vyas ◽  
Muthiah Perumal ◽  
Tommaso Moramarco
Keyword(s):  
Flow Velocity ◽  
Surface Flow ◽  
Tsallis Entropy ◽  
Accurate Estimation ◽  
Mean Flow ◽  
Flow Area ◽  
Cross Sectional ◽  
The Cross ◽  
Discharge Estimation ◽  
Mean Flow Velocity

Streamflow measurements during high floods is a challenge for which the World Meteorological Organization fosters the development of innovative technologies for achieving an accurate estimation of the discharge. The use of non-contact sensors for monitoring surface flow velocities is of interest to turn these observed values into a cross-sectional mean flow velocity, and subsequently, into discharge if bathymetry is given. In this context, several techniques are available for the estimation of mean flow velocity, starting from observed surface velocities. Among them, the entropy-based methodology for river discharge assessment is often applied by leveraging the theoretical entropic principles of Shannon and Tsallis, both of which link the maximum flow velocity measured at a vertical of the flow area, named the y-axis, and the cross-sectional mean flow velocity at a river site. This study investigates the performance of the two different entropic approaches in estimating the mean flow velocity, starting from the maximum surface flow velocity sampled at the y-axis. A velocity dataset consisting of 70 events of measurements collected at two gauged stations with different geometric and hydraulic characteristics on the Po and Tiber Rivers in Italy was used for the analysis. The comparative evaluation of the velocity distribution observed at the y-axis of all 70 events of measurement was closely reproduced using both the Shannon and Tsallis entropy approaches. Accurate values in terms of the cross-sectional mean flow velocity and discharge were obtained with average errors not exceeding 10%, demonstrating that the Shannon and Tsallis entropy concepts were equally efficient for discharge estimation in any flow conditions.

Loss analysis of the shrouded radial-inflow turbine for compressed air energy storage

2020 ◽  
pp. 095765092094784
Author(s):  
Ziyi Shao ◽  
Wen Li ◽  
Aiting Li ◽  
Xing Wang ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Energy Storage ◽  
Entropy Generation ◽  
Velocity Ratio ◽  
Compressed Air ◽  
Compressed Air Energy Storage ◽  
Suction Surface ◽  
Loss Mechanism ◽  
Cross Sectional ◽  
Radial Turbine ◽  
Radial Inflow Turbine

The shrouded radial-inflow turbine is widely employed as a power generation device in the compressed air energy storage (CAES) system. The loss mechanism and off-designed performance of the shrouded radial turbine are lesser known hitherto and should be deeply understood. Loss analyses of a shrouded radial turbine are conducted numerically based on the first and second laws of thermodynamics in the current study. The relationship between losses and the secondary flow has been discussed in detail. A high proportion of loss in the rotor and outblock passage is found under off-designed conditions. The secondary vortex cores and wake are the primary sources of energy dissipation, while the entropy generation mainly appears at the edge of secondary vortices. The suction-surface separation expands as the velocity ratio is decreased, making the high entropy generation scope on the cross-sectional plane wider. Reducing the seal clearance and avoiding the low velocity ratio conditions are quite necessary to reduce losses. It is recommended the outlet passage should be designed longer than the length of rotor axial chord for a uniform outflow.

In-Line Inspection of Engine Valve Seats Using a Non-Contact Range Sensor

2008 ◽  
Author(s):  
Vijay Srivatsan ◽  
Bartosz Powałka ◽  
Reuven Katz ◽  
John Agapiou
Keyword(s):  
Combustion Engine ◽  
Cone Angle ◽  
Valve Seat ◽  
Cross Sectional ◽  
Engine Valve ◽  
Coordinate Measurement ◽  
Range Sensor ◽  
Minimum Number ◽  
High Degree ◽  
Analyze Data

This paper presents a methodology for the inspection of geometric features on an internal combustion engine valve seat. Inspection of valve seat geometry using a high-precision non-contact range sensor is investigated. A method that can extract the cone angle, the valve seat length and the roundness of the cone surface has been presented. In-line implementation requires a methodology to analyze data from a minimum number of parallel cross sectional profiles of the valve seat. An in-line valve seat inspection prototype machine with two axes of motion that utilizes the method presented in this paper is presented. Validation of the method on several valve seat samples shows a high degree of repeatability, and the results are comparable to coordinate measurement machine measurements of the same samples.

scholarly journals Experimental Investigation and Mathematical Modelling of Pressure Transfer Function for Air Compressor

2018 ◽  
Vol 7 (4.19) ◽  
pp. 950
Author(s):  
Mishaal A. AbdulKareem
Keyword(s):  
Pressure Response ◽  
Compressed Air ◽  
Operating Pressure ◽  
Perfect Gas ◽  
Cross Sectional ◽  
Air Compressor ◽  
Output Pressure ◽  
Sinusoidal Functions ◽  
Good Agreement ◽  
Pressure Switch

A mathematical model is developed to estimate the pressure response of an insulated electric air compressor. A pressure switch is modeled as a comparator and the electric motor as an amplifier. It is assumed that the compressed air is a perfect gas when applying the isentropic process. In addition, the effect of a step, ramp and sinusoidal functions of disturbance signals on the air pressure has been studied.  A good agreement was obtained when comparing the predicted results with the measured values obtained from the experimental test that was done using a (1.32 kW, 23 litter and 8 bar) electric reciprocating air compressor. In addition, the same behavior of the predicted results was obtained when compared with results of a previously published article. It was found that the time constant of this control system is directly proportional with the value of the spring constant that is inserted inside the pressure switch and with the volume of air storage vessel, and it is inversely proportional with the gain of the amplifier and with the effective cross-sectional area of the pressure switch diaphragm and it is independent of the value of operating pressure set point. In addition, when the value of disturbance signal is positive, it will increase the output pressure response and when it is negative, it will decrease it. 

scholarly journals Sustainable and Resilient Smart House Using the Internal Combustion Engine of Plug-in Hybrid Electric Vehicles

2020 ◽  
Vol 12 (15) ◽  
pp. 6046
Author(s):  
Ahad Abessi ◽  
Elham Shirazi ◽  
Shahram Jadid ◽  
Miadreza Shafie-khah
Keyword(s):  
Electric Vehicles ◽  
Distribution System ◽  
Distribution Systems ◽  
Hybrid Electric Vehicles ◽  
Combustion Engine ◽  
Power Outage ◽  
Vehicle To Grid ◽  
Emergency Situations ◽  
Smart House ◽  
Hybrid Electric

Nowadays, due to the increasing number of disasters, improving distribution system resiliency is a new challenging issue for researchers. One of the main methods for improving the resiliency in distribution systems is to supply critical loads after disasters during the power outage and before system restorations. In this paper, a “Sustainable and resilient smart house” is introduced for the first time by using plug-in hybrid electric vehicles (PHEVs). PHEVs have the ability to use their fuel for generating electricity in emergency situations as the Vehicle to Grid (V2G) scheme. This ability, besides smart house control management, provides an opportunity for distribution system operators to use their extra energy for supplying a critical load in the system. The proposed control strategy in this paper is dedicated to a short duration power outage, which includes a large percent of the events. Then, improvement of the resiliency of distribution systems is investigated through supplying smart residential customers and injecting extra power to the main grid. A novel formulation is proposed for increasing the injected power of the smart house to the main grid using PHEVs. The effectiveness of the proposed method in increasing power injection during power outages is shown in simulation results.

Design and Development of an Improved Air Distributor for a Large Coal-Fired Fluidised Bed Combustor

2008 ◽  
Author(s):  
John Ward ◽  
Roy Garwood ◽  
Randall Bowen ◽  
Maurice Fisher ◽  
David Gent
Keyword(s):  
Distribution System ◽  
Pipe Wall ◽  
Flow Characteristics ◽  
Thin Layers ◽  
Outer Diameter ◽  
Fluidised Bed ◽  
Operating Life ◽  
Cross Sectional ◽  
Pipe Length ◽  
Pipe System

The air distribution system in a fluidised bed combustor is usually required to provide a reasonably uniform distribution of combustion air over the cross-sectional area of the entire bed. Various designs of distributor have been employed and one of the simplest and cheapest constructions is the so-called sparge pipe system, in which an array of horizontal pipes is fitted near the base of the bed. Combustion air is then supplied to one end of each pipe and enters the bed through a series of downward facing holes positioned along the pipe length. This paper describes the re-design and subsequent modification of an existing sparge pipe distributor for a large coal fired fluidised bed combustor which produced hot exhaust gases for drying of pressed sugar beet pulp. The air flow out of the holes in the existing pipes varied by a factor of approximately 3.8:1 along the length and moreover the overall flow was limited by the high pressure drop within the system. As a result the thermal output of the combustor cannot always meet the demands of the drying process. Excessive erosion and wear of the walls of the pipes near some of the holes can also be a problem. A computational fluid dynamics (CFD) study was undertaken of the flow characteristics of different designs of sparge pipe and the results validated by flow and pressure measurements on full scale laboratory models. The flow distribution was substantially improved and the overall flow rate increased by approximately 7% by varying the hole diameters and spacings between adjacent holes. In addition much greater increases in predicted overall flow rates can be achieved by reducing the thickness of the pipe wall (whilst maintaining a constant outer diameter) although this may reduce the operating life of the pipe because of erosion and excessive wear. Erosion of the outside of the pipes was studied in near ambient temperature fluidised beds using multiple thin layers of different coloured paints on the outside of the pipes to assess the wear patterns. These patterns were found to be similar to those observed on actual sparge pipes at the end of an operating campaign. Quantitative measurements of the rate of wear of the paint layers indicated that pipe wall erosion can be substantially reduced by reducing the angle of inclination of the downward facing holes in the pipes.

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