Reallocation time calculation according to slot occupation rate

ABSTRACTThe increasing use of unmanned aerial vehicles in areas such as rescue, mapping, and transportation have made it necessary to study more accurate techniques for calculating flight time estimates. Such calculations require knowing the battery discharge profile. Simplified flight time calculation methods provide data with uncertainties as they are based solely on manufacturer datasheet information. This study presents a setup to measure the battery discharge curve using a LabVIEW interface with a low-cost acquisition system. The acquired data passes through a nonlinear optimisation algorithm to find the battery coefficients, which enables the more precise estimation of its range and endurance. The great advantage of this model is that it makes it possible to predict how the battery will discharge at different rates using just one experimental curve. The methodology was applied to three different batteries and the model was validated with different discharge rates in a controlled environment, which resulted in endurance lower than 3.0% for most conditions and voltage estimation error lower than 3.0% in operational voltage. The work also presented a methodology for estimating cruise time based on the current used during each flight stage.

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Optimal switching time calculation in Predictive Torque Control

8th International Conference on Power Electronics - ECCE Asia ◽

10.1109/icpe.2011.5944645 ◽

2011 ◽

Cited By ~ 12

Author(s):

P. Landsmann ◽

P. Stolze ◽

R. Kennel

Keyword(s):

Switching Time ◽

Torque Control ◽

Optimal Switching ◽

Time Calculation

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On the Rapid Generation of Complete XRF Spectra for Material Analysis from Fundamental Parameters

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.105.110 ◽

2021 ◽

Vol 105 ◽

pp. 110-118

Author(s):

Jie Si Ma ◽

Fu Sheng Li ◽

Yan Chun Zhao

Keyword(s):

Simulated Data ◽

Target Material ◽

Mcnp Code ◽

X Ray ◽

Fundamental Parameters ◽

Elemental Compositions ◽

Statistical Precision ◽

Proposed Model ◽

Time Calculation ◽

Rapid Generation

X-ray Fluorescence (XRF) analysis technology is used widely to detect and measure elemental compositions of target samples. The MCNP code developed by LANL can be utilized to simulate and generate the XRF spectrum of any sample with various elemental compositions. However, one shortcoming of MCNP code is that it takes quite a lot of time (in hours or longer) to generate one XRF spectrum with reasonable statistical precision; the other shortcoming is that MCNP code cannot produce L shell spectrum accurately. In this paper, a new computation model based on the Sherman equation (i.e., Fundamental Parameters, FP) is proposed to overcome the drawbacks of the MCNP code. The most important feature of this model is to achieve a full and accurate generation of spectral information of each element in a target material very rapidly (in seconds or less), including both K and L shell spectral peaks. Furtherly, it is demonstrated that the simulated data by this new mode match the experimental data very well. It proves that the proposed model can be a better alternative of MCNP code in the application of generation the XRF spectra of many materials, in terms of speed and accuracy. The proposed model can perform the simulation of XRF spectra in situ both fast and accurately, which is essential for real-time calculation of chemical composition by use of X-ray spectrometer, especially for those trace elements in target materials.

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On real-time creep damage prediction for steam turbine

Transactions of the Institute of Measurement and Control ◽

10.1177/01423312211068949 ◽

2022 ◽

pp. 014233122110689

Author(s):

Yongjian Sun ◽

Bo Xu

Keyword(s):

Finite Element ◽

Steam Turbine ◽

Real Time ◽

Creep Damage ◽

Element Model ◽

Turbine Rotor ◽

Theoretical Research ◽

Element Analysis ◽

Damage Prediction ◽

Time Calculation

In this paper, in order to solve the calculation problem of creep damage of steam turbine rotor, a real-time calculation method based on finite element model is proposed. The temperature field and stress field of the turbine rotor are calculated using finite element analysis software. The temperature data and stress data of the crucial positions are extracted. The data of temperature, pressure, rotational speed, and stress relating to creep damage calculation are normalized. A real-time creep stress calculation model is established by multiple regression method. After that, the relation between stress and damage function is analyzed and fitted, and creep damage is calculated in real-time. A creep damage real-time calculation system is constructed for practical turbine engineering. Finally, a numerical simulation experiment is designed and carried out to verify the effectiveness of this novel approach. Contributions of present work are that a practical solution for real-time creep damage prediction of steam turbine is supplied. It relates the real-time creep damage prediction to process parameters of steam turbine, and it bridges the gap between the theoretical research works and practical engineering.

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Compressor Computerized Performance Monitoring System CPMS

10.2118/204582-ms ◽

2021 ◽

Author(s):

Vadim Goryachikh ◽

Fahad Alghamdi ◽

Abdulrahman Takrouni

Keyword(s):

Natural Gas ◽

Real Time ◽

Monitoring System ◽

Performance Monitoring ◽

Compressibility Factor ◽

Background Information ◽

Monitoring Systems ◽

Turbo Expander ◽

Time Calculation ◽

Performance Deterioration

Abstract Background information Natural gas liquid (NGL) production facilities, typically, utilize turbo-expander-brake compressor (TE) to generate cold for C2+ separation from the natural gas by isentropic expansion of feed stream and use energy absorbed by expansion to compress residue gas. Experience shows that during operational phase TE can exposed to operation outside of design window that may lead to machine integrity loss and consequent impact on production. At the same time, there is a lack of performance indicators that help operator to monitor operating window of the machine and proactively identify performance deterioration. For instance, TE brake compressor side is always equipped with anti-surge protection system, including surge deviation alarms and trip. However, there is often gap in monitoring deviation from stonewall region. At the same time, in some of the designs (2×50% machines) likelihood of running brake compressor in stonewall is high during one machine trip or train start-up, turndown operating modes. Also, typical compressor performance monitoring systems does not have enough dynamic parameters that may indicate machine process process performance deterioration proactively (real-time calculation of actual polytrophic efficiency, absorbed power etc.) and help operator to take action before catastrophic failure occurs. In addition, typical compressor monitoring systems are based on assumed composition and fixed compressibility factor and do not reflect actual compositions variations that may affect machine performance monitoring. To overcome issues highlighted above, Hawiyah NGL (HNGL) team has developed computerized monitoring and advisory system to monitor the performance of turbo-expander-brake compressor, proactively, identify potentially unsafe conditions or performance deterioration and advice operators on taking necessary actions to avoid unscheduled deferment of production. Computerized performance monitoring system has been implemented in HNGL DCS (Yokogawa) and utilized by control room operators on day-to-day basis. Real-time calculation, analysis and outputs produced by performance monitoring system allow operator to understand how current operating condition are far from danger zone. Proactive deviation alarms and guide messages produce by the system in case of deviation help operators to control machine from entering unsafe region. Actual polytrophic efficiency, adsorbed power calculations provide machine condition status and allow identifying long-term performance deterioration trends.

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