scholarly journals Investigation on the Performance Characteristics of 2-Stroke Heavy Fuel Light Aeroengine (2SHFLA) with Different Fuel Injection Systems: Modeling and Comparative Simulation

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5136
Author(s):  
Yuan Qiao ◽  
Li Lin ◽  
Wei Zhong ◽  
Kaisheng Huang
Keyword(s):  
Fuel Injection ◽  
Performance Characteristics ◽  
Model Parameters ◽  
Simulation Platform ◽  
Data Simulation ◽  
System A ◽  
Comprehensive Comparison ◽  
Working Principle ◽  
Set Up ◽  
Calibrated Simulation

Extensive application of small and medium-sized unmanned aerial vehicles (UAVs) have already made the development of corresponding power system a research hotspot nowadays. Two-stroke heavy fuel light aeroengine (2SHFLA) is selected as the research focus in this paper. The working principle of 2SHFLA with different fuel injection systems is elaborated systematically. By dividing the initial prototype engine into several subsystems, the simulation platform is set up with its key model parameters accurately calibrated against the test data. Simulation platforms of the other two types of engines are subsequently constructed based on the pre-calibrated simulation platform of the initial prototype engine. Afterwards, comparative simulation is performed and the corresponding simulation results include: (1) comparison of performance characteristics of the initial prototype engine fueled with regular gasoline/heavy fuel; (2) comprehensive comparison of the performance characteristics of all the three types of engine.

Modeling and Simulation of Freshwater Generator Subsystem of Low Speed Engine Room Simulator Based on Visual

2012 ◽  
Vol 557-559 ◽  
pp. 2324-2328
Author(s):  
Qian Ming Shang
Keyword(s):  
3D Models ◽  
Time Variable ◽  
Practical Situation ◽  
Generator System ◽  
System A ◽  
Working Principle ◽  
Network Communications ◽  
Sustainable System ◽  
Set Up ◽  
Speed Engine

3d models of the equipments of freshwater generator system are built according to the real ship. In support of a simulative sustainable system, a real-time variable database and mathematical models of the subsystem are set up. Then the precision of the models are proved to meet the demands by comparing the simulation results with the practical situation. The interfaces are available by making use of VC++6.0. Finally, the data connections between the math models and interfaces are established by means of the technology of network communications. The purpose of developing this simulation system is training, which offers students a chance to make a good knowledge of the structure and working principle of the freshwater generator subsystem.

scholarly journals A New Real-Time Pinch Detection Algorithm Based on Model Reference Kalman Prediction and SRMS for Electric Adjustable Desk

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4699
Author(s):  
Minming Gu ◽  
Yajie Wei ◽  
Haipeng Pan ◽  
Yujia Ying
Keyword(s):  
Pulse Width Modulation ◽  
Detection Algorithm ◽  
Prediction Algorithm ◽  
Actual System ◽  
Model Reference ◽  
Threshold Detection ◽  
System A ◽  
Working Principle ◽  
Current Sampling ◽  
Kalman Prediction

This paper presents a new algorithm based on model reference Kalman torque prediction algorithm combined with the sliding root mean square (SRMS). It is necessary to improve the accuracy and reliability of the pinch detection for avoiding collision with the height adjustable desk and accidents on users. Motors need to regulate their position and speed during the operation using different voltage by PWM (Pulse Width Modulation) to meet the requirement of position synchronization. It causes much noise and coupling information in the current sampling signal. Firstly, to analyze the working principle of an electric height adjustable desk control system, a system model is established with consideration of the DC (Direct Current) motor characteristics and the coupling of the system. Secondly, to precisely identify the load situation, a new model reference Kalman perdition method is proposed. The load torque signal is selected as a pinch state variable of the filter by comparing the current signal. Thirdly, to meet the need of the different loads of the electric table, the sliding root means square (SRMS) of the torque is proposed to be the criterion for threshold detection. Finally, to verify the effectiveness of the algorithm, the experiments are carried out in the actual system. Experimental results show that the algorithm proposed in this paper can detect the pinched state accurately under different load conditions.

scholarly journals An enhanced set of displacement parameter restraints in CRYSTALS

2018 ◽  
Vol 51 (4) ◽  
pp. 1059-1068 ◽  
Author(s):  
Pascal Parois ◽  
James Arnold ◽  
Richard Cooper
Keyword(s):  
Structural Model ◽  
Rigid Bodies ◽  
Model Parameters ◽  
Coordinate Systems ◽  
Principal Axes ◽  
Anisotropic Displacement Parameters ◽  
Set Up ◽  
Meaningful Relationships ◽  
Parameter Values ◽  
Total Model

Crystallographic restraints are widely used during refinement of small-molecule and macromolecular crystal structures. They can be especially useful for introducing additional observations and information into structure refinements against low-quality or low-resolution data (e.g. data obtained at high pressure) or to retain physically meaningful parameter values in disordered or unstable refinements. However, despite the fact that the anisotropic displacement parameters (ADPs) often constitute more than half of the total model parameters determined in a structure analysis, there are relatively few useful restraints for them, examples being Hirshfeld rigid-bond restraints, direct equivalence of parameters and SHELXL RIGU-type restraints. Conversely, geometric parameters can be subject to a multitude of restraints (e.g. absolute or relative distance, angle, planarity, chiral volume, and geometric similarity). This article presents a series of new ADP restraints implemented in CRYSTALS [Parois, Cooper & Thompson (2015), Chem. Cent. J. 9, 30] to give more control over ADPs by restraining, in a variety of ways, the directions and magnitudes of the principal axes of the ellipsoids in locally defined coordinate systems. The use of these new ADPs results in more realistic models, as well as a better user experience, through restraints that are more efficient and faster to set up. The use of these restraints is recommended to preserve physically meaningful relationships between displacement parameters in a structural model for rigid bodies, rotationally disordered groups and low-completeness data.

scholarly journals Analytical Modeling and Validation of a Preloaded Piezoceramic Current Output

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 353
Author(s):  
Bin Zhang ◽  
Hongsheng Liu ◽  
Dezhi Li ◽  
Jinhui Liang ◽  
Jun Gao
Keyword(s):  
Energy Harvesting ◽  
Integrated Circuit ◽  
Microelectromechanical Systems ◽  
Experimental Testing ◽  
Current Source ◽  
Model Parameters ◽  
Current Output ◽  
System A ◽  
A Current ◽  
Piezoelectric Characteristics

Energy harvesting using piezoceramic has drawn a lot of attention in recent years. Its potential usage in microelectromechanical systems is starting to become a reality thanks to the development of an integrated circuit. An accurate equivalent circuit of piezoceramic is important in energy harvesting and the sensing system. A piezoceramic is always considered to be a current source according to empirical testing, instead of the derivation from its piezoelectric characteristics, which lacks accuracy under complicated mechanical excitation situations. In this study, a new current output model is developed to accurately estimate its value under various kinds of stimulation. Considering the frequency, amplitude and preload variation imposed on a piezoceramic, the multivariate model parameters are obtained in relation to piezo coefficients. Using this model, the current output could be easily calculated without experimental testing in order to quickly estimate the output power in energy harvesting whatever its geometric shape and the various excitations.

Actual Discharge on Venturimeter - A Literature

2021 ◽  
pp. 1-4
Author(s):  
Amit Rakshit ◽  
Sumana Ghosh
Keyword(s):  
Automotive Industry ◽  
Air Distribution ◽  
Flow Lines ◽  
Discharge Coefficients ◽  
Working Principle ◽  
Set Up

Venturi meter is a device which is used for measuring the rate of flow of fluid flowing through the pipes. The applications of these are found in various fields like Water House Department, Aviation, Automotive, Chemical, Petro-chemical industries, etc. In automotive industry venturimeter is used to measure the fuel and air distribution in carburetor. Similarly, in the water houses, venturimeter device is used to calculate the velocity of flow in the pipelines [1]. In this paper we have to discuss about the working principle and set up the study of experimental calculations on venturimeter. In the present paper, an attempt was made to study a computational device of a venturimeter, which can be used as an efficient and easy means for predicting the discharge coefficients for the flow lines. Keywords: Venturi meter; Discharge; Heads; Co-efficient of Discharge

scholarly journals Melting and freezing under Antarctic ice shelves from a combination of ice-sheet modelling and observations

2017 ◽  
Vol 63 (240) ◽  
pp. 731-744 ◽  
Author(s):  
JORGE BERNALES ◽  
IRINA ROGOZHINA ◽  
MAIK THOMAS
Keyword(s):  
Mass Balance ◽  
Ice Sheet ◽  
Model Parameters ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Continental Scale ◽  
Model Set ◽  
Set Up ◽  
Basal Melting ◽  
The Antarctic

ABSTRACTIce-shelf basal melting is the largest contributor to the negative mass balance of the Antarctic ice sheet. However, current implementations of ice/ocean interactions in ice-sheet models disagree with the distribution of sub-shelf melt and freezing rates revealed by recent observational studies. Here we present a novel combination of a continental-scale ice flow model and a calibration technique to derive the spatial distribution of basal melting and freezing rates for the whole Antarctic ice-shelf system. The modelled ice-sheet equilibrium state is evaluated against topographic and velocity observations. Our high-resolution (10-km spacing) simulation predicts an equilibrium ice-shelf basal mass balance of −1648.7 Gt a−1 that increases to −1917.0 Gt a−1 when the observed ice-shelf thinning rates are taken into account. Our estimates reproduce the complexity of the basal mass balance of Antarctic ice shelves, providing a reference for parameterisations of sub-shelf ocean/ice interactions in continental ice-sheet models. We perform a sensitivity analysis to assess the effects of variations in the model set-up, showing that the retrieved estimates of basal melting and freezing rates are largely insensitive to changes in the internal model parameters, but respond strongly to a reduction of model resolution and the uncertainty in the input datasets.

Overview on the Liquid Metal Battery for Grid-Level Large-Scale Energy Storage

2016 ◽  
Vol 723 ◽  
pp. 572-578
Author(s):  
Li Fu ◽  
Qi Chi Le ◽  
Xi Bo Wang ◽  
Xuan Liu ◽  
Wei Tao Jia
Keyword(s):  
Energy Storage ◽  
Liquid Metal ◽  
Large Scale ◽  
Low Cost ◽  
Advantages And Disadvantages ◽  
Comprehensive Comparison ◽  
Development And Utilization ◽  
Working Principle ◽  
Liquid Metal Battery ◽  
Grid Level

In recent years, the development and utilization of renewable generation have attracted more and more attention, and the grid puts forward higher requirements to the energy storage technology, especially for security, stability and reliability. The liquid metal battery (LMB) consists of two liquid metal electrodes and a molten salt electrolyte, which will be segregated into three liquid layers naturally. Being low-cost and long-life, it is regarded as the best choice for grid-level large-scale energy storage. This paper describes the main structure and working principle of the LMB, analyzes the advantages and disadvantages of the LMB when compared with the traditional batteries, and explores the feasibility and economy when it is used as a kind of large-scale energy storage applied in the power grid. The paper also makes a comprehensive comparison on the performance of several LMBs, and points out the LMB’s research and development in the future.

scholarly journals Prediction of snowmelt derived streamflow in a wetland dominated prairie basin

2010 ◽  
Vol 7 (1) ◽  
pp. 1103-1141 ◽  
Author(s):  
X. Fang ◽  
J. W. Pomeroy ◽  
C. J. Westbrook ◽  
X. Guo ◽  
A. G. Minke ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Hydrological Model ◽  
Snow Accumulation ◽  
Model Parameters ◽  
Field Observations ◽  
Runoff Generation ◽  
Stream Channels ◽  
Physically Based ◽  
Set Up ◽  
Spot 5

Abstract. The eastern Canadian Prairies are dominated by cropland, pasture, woodland and wetland areas. The region is characterized by many poor and internal drainage systems and large amounts of surface water storage. Consequently, basins here have proven challenging to hydrological model predictions which assume good drainage to stream channels. The Cold Regions Hydrological Modelling platform (CRHM) is an assembly system that can be used to set up physically based, flexible, object oriented models. CRHM was used to create a prairie hydrological model for the externally drained Smith Creek Research Basin (~400 km2), east-central Saskatchewan. Physically based modules were sequentially linked in CRHM to simulate snow processes, frozen soils, variable contributing area and wetland storage and runoff generation. Five "representative basins" (RBs) were used and each was divided into seven hydrological response units (HRUs): fallow, stubble, grassland, river channel, open water, woodland, and wetland as derived from a supervised classification of SPOT 5 imagery. Two types of modelling approaches calibrated and uncalibrated, were set up for 2007/08 and 2008/09 simulation periods. For the calibrated modelling, only the surface depression capacity of upland area was calibrated in the 2007/08 simulation period by comparing simulated and observed hydrographs; while other model parameters and all parameters in the uncalibrated modelling were estimated from field observations of soils and vegetation cover, SPOT 5 imagery, and analysis of drainage network and wetland GIS datasets as well as topographic map based and LiDAR DEMs. All the parameters except for the initial soil properties and antecedent wetland storage were kept the same in the 2008/09 simulation period. The model performance in predicting snowpack, soil moisture and streamflow was evaluated and comparisons were made between the calibrated and uncalibrated modelling for both simulation periods. Calibrated and uncalibrated predictions of snow accumulation were very similar and compared fairly well with the distributed field observations for the 2007/08 period with slightly poorer results for the 2008/09 period. Soil moisture content at a point during the early spring was adequately simulated and very comparable between calibrated and uncalibrated results for both simulation periods. The calibrated modelling had somewhat better performance in simulating spring streamflow in both simulation periods, whereas the uncalibrated modelling was still able to capture the streamflow hydrographs with good accuracy. This suggests that prediction of prairie basins without calibration is possible if sufficient data on meteorology, basin landcover and physiography are available.

scholarly journals Experimental and Numerical Study of a Thermal Expansion Gyroscope for Different Gases

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 360 ◽  
Author(s):  
Guillaume Kock ◽  
Philippe Combette ◽  
Marwan Tedjini ◽  
Markus Schneider ◽  
Caroline Gauthier-Blum ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Gas Flow ◽  
Numerical Study ◽  
Rotational Velocity ◽  
Measurement Range ◽  
Gas Temperature ◽  
Hot Air ◽  
Working Principle ◽  
Set Up ◽  
Different Gases

A new single-axis gas thermal gyroscope without proof mass is presented in this paper. The device was designed, manufactured and experimentally characterized. The obtained results were compared to numerical simulation. The working principle of the gyroscope is based on the deflection of a laminar gas flow caused by the Coriolis effect. A bidirectional hot air flow is generated by alternating activation of two suspended resistive micro-heaters. The heated gas is encapsulated in a semi-open cavity and the gas expands primarily inside the cavity. The thermal expansion gyroscope has a simple structure. Indeed, the device is composed of a micromachined cavity on which three bridges are suspended. The central bridge is electrically separated into two segments enabling to set up two heaters which may be supplied independently from each other. The two other bridges, placed symmetrically on each side of the central bridge, are equipped with temperature detectors which measure variations in gas temperature. The differential temperature depends on the rotational velocity applied to the system. Various parameters such as the heating duty cycle, the type of the gas and the power injected into the heaters have been studied to define the optimal working conditions required to obtain the highest level of sensitivity over a measurement range of around 1000°/s. The robustness of the device has also been tested and validated for a shock resistance of 10,000 g for a duration of 400 µs.

The effect of increased inputs to twin-bearing ewes within an extensive hill sheep system

1995 ◽  
Vol 1995 ◽  
pp. 64-64
Author(s):  
S. E. Pattinson ◽  
A. Waterhouse
Keyword(s):  
At Risk ◽  
Large Scale ◽  
Local Community ◽  
Animal Production ◽  
General Belief ◽  
Large Scale Systems ◽  
Extensive System ◽  
System A ◽  
Sheep Production ◽  
Set Up

There is a general belief that reduced stock numbers on hill areas will be beneficial to the environment. A decrease in stock numbers may lead to farmers opting for lower input systems of hill sheep production in order to reduce costs, to meet the requirements of specific schemes or simply to maintain profitability. A large scale systems experiment has been set up at SAC Kirkton and Auchtertyre Farms to examine the effects of extensification on the ecology, animal production and welfare and the socio-economics of the local community. Within this extensive system, a 4-year trial was undertaken to examine the effects of a limited increase in inputs to twin-bearing ewes which are particularly at risk within such a system.

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