scholarly journals Working Characteristics of Variable Intake Valve in Compressed Air Engine

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Qihui Yu ◽  
Yan Shi ◽  
Maolin Cai
Keyword(s):  
Mathematical Model ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Compressed Air ◽  
Maximum Output ◽  
Output Torque ◽  
Good Consistency ◽  
Intake Pressure ◽  
Set Up ◽  
The Mathematical Model

A new camless compressed air engine is proposed, which can make the compressed air energy reasonably distributed. Through analysis of the camless compressed air engine, a mathematical model of the working processes was set up. Using the software MATLAB/Simulink for simulation, the pressure, temperature, and air mass of the cylinder were obtained. In order to verify the accuracy of the mathematical model, the experiments were conducted. Moreover, performance analysis was introduced to design compressed air engine. Results show that, firstly, the simulation results have good consistency with the experimental results. Secondly, under different intake pressures, the highest output power is obtained when the crank speed reaches 500 rpm, which also provides the maximum output torque. Finally, higher energy utilization efficiency can be obtained at the lower speed, intake pressure, and valve duration angle. This research can refer to the design of the camless valve of compressed air engine.

Research on Dynamic Balance Method of Precision Centrifuge

2014 ◽  
Vol 945-949 ◽  
pp. 777-780
Author(s):  
Tao Liu ◽  
Yong Xu ◽  
Bo Yuan Mao
Keyword(s):  
Mathematical Model ◽  
Balance Control ◽  
Dynamic Balance ◽  
Dynamic Balancing ◽  
Structure Characteristics ◽  
Balance System ◽  
Simulation Results ◽  
Set Up ◽  
System Controller ◽  
The Mathematical Model

Firstly, according to the structure characteristics of precision centrifuge, the mathematical model of its dynamic balancing system was set up, and the dynamic balancing scheme of double test surfaces, double emendation surfaces were established. Then the dynamic balance system controller of precision centrifuge was designed. Simulation results show that the controller designed can completely meet the requirements of precision centrifuge dynamic balance control system.

Pressure Changes Induced by Whole Body Acceleration Shocks

1991 ◽  
Vol 113 (1) ◽  
pp. 27-29 ◽  
Author(s):  
E. Belardinelli ◽  
M. Ursino ◽  
G. Fabbri ◽  
A. Cevese ◽  
F. Schena
Keyword(s):  
Mathematical Model ◽  
Carotid Artery ◽  
Normal Pressure ◽  
Compressed Air ◽  
Whole Body ◽  
Body Acceleration ◽  
Vascular Bed ◽  
Pressure Changes ◽  
The Mathematical Model

In the present paper pressure changes induced by sudden body acceleration are studied “in vivo” on the dog and compared to the results obtainable with a recently developed mathematical model. A dog was fixed to a movable table, which was accelerated by a compressed air piston for less than 1 s. Acceleration was varied by changing the air pressure in the piston. Pressure was measured during the experiment at different points along the vascular bed. However, only data obtained in the carotid artery and abdominal aorta are presented here. The results demonstrated that impulse body accelerations cause significant pressure peaks in the vessel examined (about + 25 mmHg in the carotid artery with body acceleration of g/2). Moreover, pressure changes are rapidly damped, with a time constant of about 0.1s. From the present results it may be concluded that, according to the prediction of the mathematical model, body accelerations such as those occurring in normal life can induce pressure changes well beyond the normal pressure value.

scholarly journals A Mathematical Model Combined with Radar Data for Bell-Less Charging of a Blast Furnace

Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 239 ◽  
Author(s):  
Meng Li ◽  
Han Wei ◽  
Yao Ge ◽  
Guocai Xiao ◽  
Yaowei Yu
Keyword(s):  
Mathematical Model ◽  
Blast Furnace ◽  
Gas Flow ◽  
Radar Data ◽  
Radar System ◽  
Utilization Efficiency ◽  
Burden Distribution ◽  
Gas Utilization ◽  
Reduce Energy Consumption ◽  
The Mathematical Model

Charging directly affects the burden distribution of a blast furnace, which determines the gas distribution in the shaft of the furnace. Adjusting the charging can improve the distribution of the gas flow, increase the gas utilization efficiency of the furnace, reduce energy consumption, and prolong the life of the blast furnace. In this paper, a mathematical model of blast furnace charging was developed and applied on a steel plant in China, which includes the display of the burden profile, burden layers, descent speed of the layers, and ore/coke ratio. Furthermore, the mathematical model is developed to combine the radar data of the burden profile. The above model is currently used in Nanjing Steel as a reference for operators to adjust the charging. The model is being tested with a radar system on the blast furnace.

Theoretical and Experimental Study of the Dynamics of the Tripod-Ball Sliding Joint With Clearance

2001 ◽  
Author(s):  
Jia Xiaohong ◽  
Ji Linhong ◽  
Jin Dewen ◽  
Zhang Jichuan
Keyword(s):  
Mathematical Model ◽  
Equations Of Motion ◽  
Experimental Studies ◽  
Active System ◽  
New Concepts ◽  
Sliding Joint ◽  
New Type ◽  
Set Up ◽  
The Mathematical Model ◽  
Kane Method

Abstract Clearance is inevitable in the kinematic joints of mechanisms. In this paper the dynamic behavior of a crank-slider mechanism with clearance in its tripod-ball sliding joint is investigated theoretically and experimentally. The mathematical model of this new-type joint is established, and the new concepts of basal system and active system are put forward. Based on the mode-change criterion established in this paper, the consistent equations of motion in full-scale are derived by using Kane method. The experimental rig was set up to measure the effects of the clearance on the dynamic response. Corresponding experimental studies verify the theoretical results satisfactorily. In addition, due to the nonlinear elements in the improved mathematical model of the joint with clearance, the chaotic responses are found in numerical simulation.

Experimental Research on Performance of Heat Transfer and Pressure Drop for Primary Surface Recuperator With Mini Channels

2011 ◽  
Author(s):  
Hugen Ma ◽  
Hui Gao ◽  
Wenjing Tu
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Pressure Drop ◽  
Experimental Research ◽  
Transfer Factor ◽  
Flow And Heat Transfer ◽  
Good Consistency ◽  
Mini Channels ◽  
Performance Of Heat Transfer ◽  
The Mathematical Model

Based on the single blow technique, experimental research was conducted for the performance of heat transfer and flow drop for six test cores with cross corrugated (CC) or corrugated undulated (CU) primary surfaces for different geometries. After the mathematical model was established for heat transfer under the condition of single blow, a matching numerical solution was obtained for different NTU. The correlations of hear transfer factor j and friction factor f were obtained for three types of cross corrugated primary surfaces (crossed angle 45∼75°) with a range of Re = 120∼800 and three types of corrugated undulated primary surfaces (crossed angle 52.5∼67.5°) with a range of Re = 200∼1200. Hydraulic diameters of all heat transfer surfaces are from 1.2∼1.48mm. Analysis on the flow and heat transfer for cross corrugated and corrugated undulated primary surfaces was made based on the comprehensive evaluating factor j/f. The experimental results were compared to references with good consistency. The regressive errors of correlations were less than 16%.

Numerical Analysis of Heat and Mass Transfer Performance of the Packed-Type Parallel Flow Dehumidifier

2014 ◽  
Vol 989-994 ◽  
pp. 3100-3104
Author(s):  
Rui Hang Zhang ◽  
Zi Ye Wang ◽  
Run Ping Niu
Keyword(s):  
Mathematical Model ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Parallel Flow ◽  
Transfer Performance ◽  
Transfer Coefficients ◽  
Simulation Results ◽  
Set Up ◽  
The Impact ◽  
The Mathematical Model

TA mathematical model describing heat and mass transfer performance of packed-type parallel flow dehumidifier was set up. The numerical solution of differential equations was derived. Taking the heat and mass transfer coefficients obtained by experiments as the input parameters of the model, the impact of solution inlet parameters on outlet parameter of air was described. The simulation results indicated that the mathematical model could be used to predict the performance of liquid dehumidification. The results showed that the mathematical model can be of great value in the design and improvement of dehumidifier.

scholarly journals Modelling Methodology of Piston Pneumatic Air Engine Operation

2019 ◽  
Vol 13 (4) ◽  
pp. 271-278
Author(s):  
Dariusz Szpica ◽  
Michal Korbut
Keyword(s):  
Mathematical Model ◽  
Exhaust System ◽  
Compressed Air ◽  
System Control ◽  
Engine Operation ◽  
Air Supply ◽  
Mechanical Subsystem ◽  
Modelling Methodology ◽  
Lumped Elements ◽  
The Mathematical Model

Abstract The article presents a mathematical model describing the operation of a piston pneumatic air engine. Compressed air engines are an alternative to classic combustion solutions as they do not directly emit toxic exhaust components. In the study, a modified internal combustion piston engine was adopted as pneumatic engine. The mathematical model was divided on the two subsystems, that is, mechanical and pneumatic. The mechanical subsystem describes a transformation of compressed air supply process parameters to energy transferred to the piston and further the conversion of the translational to rotary motion; in turn, in the pneumatic part, the lumped elements method was used. Calculations were carried out using the Matlab-Simulink software, resulting in the characteristics of external and economic indicators. The presented mathematical model can be ultimately developed with additional elements, such as the intake or exhaust system, as well as timing system control.

scholarly journals WAVE ATTENUATION AND WAVE SET-UP ON A COASTAL REEF

1980 ◽  
Vol 1 (17) ◽  
pp. 27 ◽  
Author(s):  
Franciscus Gerritsen
Keyword(s):  
Mathematical Model ◽  
Wave Attenuation ◽  
Scale Effects ◽  
Shallow Reef ◽  
Laboratory Investigations ◽  
Deep Water Wave ◽  
Set Up ◽  
The University ◽  
Incident Waves ◽  
The Mathematical Model

In attempting to specify criteria for the design of structures on coastal reefs, it was found that no adequate method existed to derive those criteria from the deep water wave conditions. In order to fill the gap, a program of measurements and analysis was initiated at the University of Hawaii. The program consisted of prototype and laboratory measurements. Great emphasis was placed on reliable field data, which were collected on Ala Moana Reef, in Honolulu. Laboratory investigations on the behavior of waves on shallow reefs are subject to scale effects; verification from field observations is required to obtain reliable results. As a result of this study, a mathematical model was developed for the calculation of wave attenuation and wave set-up on a shallow reef, using the incident waves in the ocean as boundary conditions. This paper discusses the general behavior of waves approaching a shallow reef and presents some essential characteristics of the mathematical model. The study is limited to waves approaching the shoreline at right angles. The results of this study can be extended to breakwaters with wide, submerged berms.

Research of Riveting Structure Identification and Characteristic Parameter Analysis Based on SVM

2014 ◽  
Vol 1049-1050 ◽  
pp. 1554-1557
Author(s):  
Jian Feng Yang ◽  
Gang Jiang ◽  
Jian Fei Chen
Keyword(s):  
Mathematical Model ◽  
Image Processing ◽  
Research Result ◽  
Characteristic Parameter ◽  
Parameter Analysis ◽  
Structure Identification ◽  
Support Vector ◽  
Vector Machines ◽  
Set Up ◽  
The Mathematical Model

In order to help department to make a decision whether the equipment need maintenance, some people trained the sample of characteristic parameter for riveting structure, and set up the model to recognize target by computer vision. However, we are difficult to find the research result about the affiliation between the characteristic parameter of the riveting structure and the model. In this paper, we make the image processing first, and use SVM (Support Vector Machines) algorithm to train the sample of characteristic parameter for rivet head. Finally, we research the affiliation between the characteristic parameter for the rivet head and the mathematical model, and test the accuracy of the model.

scholarly journals Performance analysis of a four-stroke compressed air engine

2020 ◽  
Vol 24 (1 Part A) ◽  
pp. 113-126
Author(s):  
Fancong Zeng ◽  
Jinli Xu
Keyword(s):  
Mathematical Model ◽  
Experimental System ◽  
Compressed Air ◽  
Work Efficiency ◽  
Supply Pressure ◽  
Numerical Studies ◽  
Optimizing Design ◽  
Working Principle ◽  
Working Performance ◽  
Set Up

The purpose of this paper is to investigate working performance for a four-stroke compressed air engine via numerical studies. A mathematical model is developed to study the influence of several operative parameters on working performance. The mathematical model consists of thermodynamic model, each stroke model and dynamic model. In addition, a working principle and an experimental system of the compressed air engine are set up. The aims are: to introduce the novel four-stroke engine and to quantify the influence of rotational speed, supply pressure and supply temperature on working characteristics. The simulation and analysis show several meaningful results. The compressed air engine has higher cylinder pressure and work efficiency in lower speed stage, and the increase of the supply pressure can effectively improve indicated work and work efficiency. However, supply temperature has little effect on the performance of the compressed air engine. Therefore, the study of this work will provide a certain guidance function for further study on optimizing design of the compressed air engine.

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