An analytical model of diesel injector’s needle valve eccentric motion

2021 ◽  
pp. 146808742098736
Author(s):  
Chuqiao Wang ◽  
Moro Adams ◽  
Tianyu Jin ◽  
Yu sun ◽  
Andreas Röll ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Injection Pressure ◽  
Analytical Models ◽  
Needle Valve ◽  
Lateral Movement ◽  
Needle Guidance ◽  
Continuous Increase ◽  
Valve Assembly ◽  
Movement And Deformation ◽  
Eccentric Motion

Past experimental studies have shown that the needle valve of high-pressure diesel injectors undergoes lateral movement and deformation, while the continuous increase in injection pressure enlarges the gap of the needle valve assembly. Two different analytical models, considering or omitting this change are presented here, linking the geometries of the needle valve assembly with the magnitude of needle valve tip lateral movement. It is found that the physical dimensions of the needle valve assembly and the injection pressure have a significant impact on the radial displacement of the needle. For example, for nominal clearances between the needle guidance and the needle valve of about 1–3 μm, the magnitude of the radial movement of the needle tip could reach tens of microns. The model that takes into account the variation of the gap between the needle guide and needle valve is found to give predictions closer to the experimental results.

scholarly journals Opportunistic Large Array Propagation Models: A Comprehensive Survey

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4206
Author(s):  
Farhan Nawaz ◽  
Hemant Kumar ◽  
Syed Ali Hassan ◽  
Haejoon Jung
Keyword(s):  
Energy Efficient ◽  
Large Scale ◽  
Performance Metrics ◽  
Experimental Studies ◽  
Cooperative Transmission ◽  
Analytical Models ◽  
Future Research ◽  
Large Array ◽  
Propagation Models ◽  
Comprehensive Survey

Enabled by the fifth-generation (5G) and beyond 5G communications, large-scale deployments of Internet-of-Things (IoT) networks are expected in various application fields to handle massive machine-type communication (mMTC) services. Device-to-device (D2D) communications can be an effective solution in massive IoT networks to overcome the inherent hardware limitations of small devices. In such D2D scenarios, given that a receiver can benefit from the signal-to-noise-ratio (SNR) advantage through diversity and array gains, cooperative transmission (CT) can be employed, so that multiple IoT nodes can create a virtual antenna array. In particular, Opportunistic Large Array (OLA), which is one type of CT technique, is known to provide fast, energy-efficient, and reliable broadcasting and unicasting without prior coordination, which can be exploited in future mMTC applications. However, OLA-based protocol design and operation are subject to network models to characterize the propagation behavior and evaluate the performance. Further, it has been shown through some experimental studies that the most widely-used model in prior studies on OLA is not accurate for networks with networks with low node density. Therefore, stochastic models using quasi-stationary Markov chain are introduced, which are more complex but more exact to estimate the key performance metrics of the OLA transmissions in practice. Considering the fact that such propagation models should be selected carefully depending on system parameters such as network topology and channel environments, we provide a comprehensive survey on the analytical models and framework of the OLA propagation in the literature, which is not available in the existing survey papers on OLA protocols. In addition, we introduce energy-efficient OLA techniques, which are of paramount importance in energy-limited IoT networks. Furthermore, we discuss future research directions to combine OLA with emerging technologies.

Characterization of the Nonroad Modified Diesel Engine Using a Novel Entropy-VIKOR Approach: Experimental Investigation and Numerical Simulation

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Pushpendra Kumar Sharma ◽  
Dilip Sharma ◽  
Shyam Lal Soni ◽  
Amit Jhalani
Keyword(s):  
Numerical Simulation ◽  
Diesel Engine ◽  
Engine Performance ◽  
Injection Pressure ◽  
Multicriteria Decision Making ◽  
Operating Parameters ◽  
Injection Timing ◽  
Oxides Of Nitrogen ◽  
Compression Ignition Engine ◽  
Continuous Increase

Excessive use of diesel engines and continuous increase in environmental pollution has drawn the attention of researchers in the area of the compression ignition engine. In this research article, an innovative investigation of the nonroad modified diesel engine is reported with the effective use of the hybrid Entropy-VIKOR approach. Hence, it becomes necessary to prioritize and optimize the performance defining criteria, which provides higher BTE along with lower emission simultaneously. The engine load, injection timing (Inj Tim), injection pressure (Inj Pre), and compression ratio (Com R) were selected as engine operating parameters for experimentation at the constant speed of 1500 rpm engine. The effect on engine performance parameters (BTE and BSEC) and emission (carbon monoxide (CO), total oxide of carbon (TOC), oxides of nitrogen (NOx), hydrocarbon (HC), and smoke) was studied experimentally. The optimum results were observed at load 10.32 kg, Inj Tim 20 deg btdc, Inj Pre 210 bar, and Com R 21:1 at which highest BTE of 22.24% and lowest BSEC of 16,188.5 kJ/kWh were obtained. Hybrid entropy-VIKOR approach was applied to establish the optimum ranking of the nonroad modified diesel engine. The experimental results and numerical simulation show that optimizing the engine operating parameters using the entropy-VIKOR multicriteria decision-making (MCDM) technique is applicable.

Turbulence Characteristics in a Rushton Stirring Vessel Measured via Time Resolved DPIV

2006 ◽  
Author(s):  
Michael R. Brady ◽  
Demetri P. Telionis ◽  
Pavlos P. Vlachos
Keyword(s):  
Experimental Studies ◽  
Turbulent Energy ◽  
Industrial Applications ◽  
Solid Particles ◽  
Analytical Models ◽  
Frequency Resolution ◽  
Time Resolved ◽  
Turbulence Characteristics ◽  
Stirred Vessels ◽  
Rushton Impeller

Stirred vessels are devices that find extensive industrial applications particularly in mineral and chemical industries. Interactions of solid particles and/or bubbles and particles depend on the characteristics of turbulent flow. In many analytical models, the rate of collision is a function of turbulence dissipation. It has been known that dissipation levels are much higher in the neighborhood of the agitating mechanism, in our case the Rushton impeller. In this paper we use time-resolved DPIV to measure the velocity field with a spatial resolution down to 100 μm, and a frequency resolution of 500 Hz. The range of Reynolds numbers investigated varied from 20,000 to 50,000, with the smallest Kolmogorov length scale of about 15 μm. The flow in the impeller stream of a Rushton impeller can be best summarized as a radial jet with a pair of convecting tip vortices. The turbulence quantities were found by removing the periodic component from the blade passing, which is the dominant part of the measured velocities. Dissipation was calculated from the velocity gradients, and assuming isotropy. We provide further evidence that larger dissipation values in the vicinity of the impeller are consistent with the dynamic motion generated by the blade passage. This is somewhat anti-intuitive, because energy is dissipated at the smallest eddy scales, and the immediate vicinity of the impeller contains large vortical structures and provides little space or time for such structures to break down. The maximum and mean normalized dissipation in the impeller stream showed decreasing trends with the Reynolds number. Other normalized turbulence quantities, namely Vrms and in plane vorticity are presented. Our experiments agree very well with other experimental studies. Estimates of turbulence characteristics and in particular distributions of turbulent energy dissipation determined in this study will be used in estimating rates of collisions of bubbles and particles in stirred vessels.

Simulation and Measurement of Fuel Injection Quantity Based on TB4P

2014 ◽  
Vol 26 (1) ◽  
pp. 34-39 ◽  
Author(s):  
Dongmin Li ◽  
◽  
Jianzhong Zhang ◽  
Jianjun Yuan ◽  
FancanGuo ◽  
...  
Keyword(s):  
Relative Error ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Valve Lift ◽  
Needle Valve ◽  
Fuel Injector ◽  
Injection Pump ◽  
Injection Quantity ◽  
Fuel Injection Pump ◽  
Fuel Injection Pressure

In order to improve the measurement accuracy of fuel injection quantity based on Test Bench for fuel injection Pump (abbr. TB4P), on the basis of the function between needle valve lift and fuel injection quantity, two-level pressure adjustment module, which combines proportional flow rate valve with pressure sensor and takes advantage of spring of fuel injector, is used to control the outlet pressure of fuel injection pump, which results in the fuel injection pressure stably. Fuel injection pump and fuel injector are modeled by use of HCD of AMESim, and the system model of fuel injection quantity measurement is built. Simulation curve of fuel injection quantity is got by AMESim, which is compared with the curve of standard fuel injection quantity according to relative error. The results show that the relative error from the data of simulation system is smaller, so the methods of measurement and simulation in this paper are effective.

Flow-Induced Noise and Vibration in Aircraft Cylindrical Cabins: Closed-Form Analytical Model Validation

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Joana da Rocha ◽  
Afzal Suleman ◽  
Fernando Lau
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Turbulent Flow ◽  
Closed Form ◽  
Experimental Studies ◽  
Interior Noise ◽  
Analytical Models ◽  
Simply Supported ◽  
Aircraft Cabin ◽  
Flow Induced Noise

The turbulent boundary layer is a major source of interior noise in transport vehicles, mainly in aircraft during cruise flight. Furthermore, as new and quieter jet engines are being developed, the turbulent flow-induced noise will become an even more important topic for investigation. However, in order to design and develop systems to reduce the cabin interior noise, the understanding of the physical system dynamics is fundamental. In this context, the main objective of the current research is to develop closed-form analytical models for the prediction of turbulent boundary-layer-induced noise in the interior of aircraft cylindrical cabins. The mathematical model represents the structural-acoustic coupled system, consisted by the aircraft cabin section coupled with the fuselage structure. The aircraft cabin section is modeled as a cylindrical acoustic enclosure, filled with air. The fuselage structure, excited by external random excitation or by turbulent flow, is represented through two different models: (1) as a whole circular cylindrical shell with simply supported end caps and (2) as a set of individual simply supported open circular cylindrical shells. This paper presents the results obtained from the developed analytical framework and its validation through the successful comparison with several experimental studies. Analytical predictions are obtained for the shell structural vibration and sound pressure levels, for the frequency range up to 10,000 Hz.

scholarly journals EXPERIMENTAL MODELING OF TSUNAMI BORE IMPINGEMENT ON A SIMPLIFIED COASTAL BUILDING

2018 ◽  
pp. 43
Author(s):  
Wei-Liang Chuang ◽  
Kuang-An Chang ◽  
James Kaihatu ◽  
Rodrigo Cienfuegos ◽  
Cyril Mokrani
Keyword(s):  
Tsunami Wave ◽  
Fluid Velocity ◽  
Experimental Studies ◽  
Wave Structure ◽  
Analytical Models ◽  
Comprehensive Investigation ◽  
Image Velocimetry ◽  
Sloping Beach ◽  
The Impact ◽  
Wave Structure Interaction

Numerous laboratory efforts were devoted to improve our understanding to the process of tsunami wave-structure interaction and provide valuable data to validate numerical and analytical models. However, the highly turbulent and multiphase nature of tsunami bores makes the study of their impacts very challenging. Many experimental studies (e.g., Shafiei et al. 2016) employed wave gauges to measure the bore height and estimate the bore front velocity based on shallow water equations. Considering the complexity of the flow and its impact with structures, the conversion between the bore height and the bore velocity is far from straightforward. Therefore, this study attempts to apply the bubble image velocimetry (BIV, Ryu et al. 2005) technique to directly measure the flow velocities during the tsunami bore impact. A tsunami wave, that breaks on a sloping beach, propagates inland as a form of bore, and impinges on a rigid structure, is considered as the scenario of interest. The objective is to perform a comprehensive investigation on the borestructure interaction by examining the fluid velocity, impact pressure, and surge force during the impact event with various structure headings.

scholarly journals Geological sequestration of CO2 in a water-bearing reservoir in hydrate-forming conditions

2020 ◽  
Vol 75 ◽  
pp. 51
Author(s):  
Raghvendra Pratap Singh ◽  
Karanpal Singh Shekhawat ◽  
Malay K. Das ◽  
Krishnamurthy Muralidhar
Keyword(s):  
Water Saturation ◽  
Formation Rate ◽  
Hydrate Formation ◽  
Injection Pressure ◽  
Injection Well ◽  
Reservoir Temperature ◽  
Isothermal Model ◽  
Initial Water ◽  
Continuous Increase ◽  
Hydrate Reservoir

Higher concentration of carbon dioxide in the atmospheric air is a major environmental challenge and requires immediate attention for quicker mitigation. In that respect, the novel idea of CO2 sequestration in geological settings is worth examining from a quantitative perspective. In the present study, numerical simulation of CO2 injection into a porous reservoir is performed. The selected reservoir presents suitable thermodynamic conditions for CO2 hydrate formation. Unsteady simulations are carried out in one space dimension under isothermal and non-isothermal frameworks. An additional simulation of CO2 injection in a depleted methane hydrate reservoir is also reported. In the present study, the response of the reservoir to storage of CO2 is analyzed with respect to four parameters – reservoir porosity, initial water saturation and reservoir temperature and injection pressure. Quantities of interest are hydrate formation patterns and the cumulative CO2 mass sequestration in the reservoir as a function of time. Numerical experiments show that the initial water saturation is an important parameter as it affects both CO2 gas migration and hydrate formation. Isothermal simulation yields results that are similar to the non-isothermal model, thus suggesting that the isothermal assumption may be adopted for future CO2 injection studies. Hydrate formation rate of CO2 near the injection well is found to be one order of magnitude higher than the interior but its magnitude is quite small when compared to water and gas saturations. Higher injection pressure leads to a continuous increase in injected mass of CO2 primarily due to increased gas density, though an increase in hydrate formation near the injection well is also observed. Lower reservoir temperature supports a higher amount of hydrate formation from the injected mass of CO2 and is clearly desirable.

Trust-Based Analytical Models for Secure Wireless Sensor Networks

2018 ◽  
pp. 47-65 ◽  
Author(s):  
Aminu Bello Usman ◽  
Jairo Gutierrez
Keyword(s):  
Wireless Sensor Networks ◽  
Experimental Studies ◽  
Analytical Models ◽  
Wireless Sensor ◽  
Analytical Relationship ◽  
Trust Evaluation ◽  
Trust And Reputation ◽  
Network Properties ◽  
Reputation Model ◽  
Evaluation Accuracy

In this chapter, the authors hypothesize that in the design of a trust-based routing protocol, the exploration of the peers' routing attributes could significantly improve trust evaluation accuracy. In this regard, they study the properties of complex networks and their impact on trust and reputation propagation and evaluation. They start by illustrating the structural transitivity in the network and its approximation. They then proceed to present the theoretical and analytical relationship between trust and reputation model accuracy, average structural transitivity between peers, average shortest path between peers, and energy consumed by peers for trust and reputation propagation and evaluations. The experimental studies using simulation have further supported the results of the analytical study. In this chapter, the authors are paving a new angle of research on exploring the complex network properties impact on trust and reputation evaluation between wireless peers.

The Development Problems of Two-Fuel Burner for the Gas Turbine Combustion Chamber

2021 ◽  
Author(s):  
A. Yu Vasilyev ◽  
O. G. Chelebyan ◽  
A. I. Maiorova ◽  
A. N. Tarasenko ◽  
D. S. Tarasov ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Liquid Fuel ◽  
Fuel Injection ◽  
Reverse Flow ◽  
Experimental Studies ◽  
Injection Pressure ◽  
Spray Angle ◽  
Preliminary Experimental Data ◽  
Fuel Injection Pressure ◽  
Air Channels

Abstract The work is devoted to the design of a spraying device for the combustion chamber GTE-65.1 on liquid fuel. The paper presents the following results: 1) The 3D calculations of the air channels characteristics for two burners types — pilot and main — were carried out. Data were obtained on the flow and pressure fields inside and at the burners outlet, and also the volumes of the reverse flow zones. 2) The main and pilot nozzles have been designed for the two spraying devices types. The values of droplet dispersity and spray angle were obtained, depending on the fuel injection pressure. 3) Based on the calculations carried out, the models of two spraying liquid fuel devices were designed and manufactured, the design of which is based on the design of the single-fuel combustion chamber (CC) on natural gas burners for GTE-65.1. At the next stage of the work, it is planned to carry out experimental studies of the two devices models aimed at obtaining an aerosol mixture with the desired properties to ensure uninterrupted operation of the GTE-65.1 on liquid fuel. Some preliminary experimental data are presented in this paper.

A Phenomenological Model for Cyclic Plasticity

1997 ◽  
Vol 119 (1) ◽  
pp. 7-11 ◽  
Author(s):  
Dar-Yun Chiang
Keyword(s):  
Cyclic Loading ◽  
Phenomenological Model ◽  
Material Properties ◽  
Experimental Studies ◽  
Cyclic Hardening ◽  
Analytical Models ◽  
Cyclic Plasticity ◽  
Loading Conditions ◽  
Microstructural Behavior ◽  
Distributed Elements

A phenomenological model is proposed for cyclic plasticity based on the concept of distributed elements, which is capable of reflecting microstructural behavior of real materials under multiaxial cyclic loading conditions. By investigating the detailed behavior of the model, various important phenomena and effects of materials in cyclic plasticity can be elucidated. Generalization of the model is also done to include cyclic hardening effects. A thorough understanding of these complicated response mechanisms and material properties provides useful insight and guidelines for validating analytical models and for performing experimental studies in the related areas of cyclic plasticity.

Sign in / Sign up

Export Citation Format

Share Document