Passive shape shifting: A compliant design approach for full film bearings

2021 ◽  
pp. 095440622110036
Author(s):  
Joep Nijssen ◽  
Ron van Ostayen
Keyword(s):  
Operating Regime ◽  
Operating Conditions ◽  
Design Approach ◽  
Variable Velocity ◽  
Active Components ◽  
Alternative Design ◽  
Bearing Design ◽  
Load Conditions ◽  
Self Adaptive

In tribotronic bearing design active components are used to adapt bearing performance to operating conditions. The principle of self-adaptive bearings has also been presented in literature in which a passive modification of geometry was used for a variation in conditions. This work presents an alternative design approach for self-adaptive bearings. This approach is focused on the shift between two known bearing geometries, where each of them is the preferred solution in a part of the operating regime. Using compliant elements in the bearing design allows for passive shape shifting. Four examples are presented which present this behavior for variable velocity and load conditions. The design approach could possibly provide a cheaper alternative for simple active bearing designs, or could be combined with active components in a tribotronics design to improve existing performance.

Optimal placement of distributed generation based on DISCO’s additional benefit using self adaptive levy flight based black widow optimization

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Naga Lakshmi Gubbala Venkata ◽  
Jaya Laxmi Askani ◽  
Venkataramana Veeramsetty
Keyword(s):  
Distributed Generation ◽  
Distribution Network ◽  
Additional Benefit ◽  
Operating Conditions ◽  
Optimal Placement ◽  
Lévy Flight ◽  
Black Widow ◽  
Levy Flight ◽  
Simulation Performance ◽  
Self Adaptive

Abstract Optimal placement of Distributed Generation (DG) is a crucial challenge for Distribution Companies (DISCO’s) to run the distribution network in good operating conditions. Optimal positioning of DG units is an optimization issue where maximization of DISCO’s additional benefit due to the installation of DG units in the network is considered to be an objective function. In this article, the self adaptive levy flight based black widow optimization algorithm is used as an optimization strategy to find the optimum position and size of the DG units. The proposed algorithm is implemented in the IEEE 15 and PG & E 69 bus management systems in the MATLAB environment. Based on the simulation performance, it has been found that with the correct location and size of the DG modules, the distribution network can be run with maximum DISCO’s additional benefit.

Fuel Atomization in Small Jet Engines

2002 ◽  
Author(s):  
Yeshayahou Levy ◽  
Semion Lipkin ◽  
Valery Nadvany ◽  
Valery Sherbaum
Keyword(s):  
Fuel Injection ◽  
High Energy ◽  
Operating Conditions ◽  
Fuel Vapor ◽  
Ignition Process ◽  
Jet Engines ◽  
Alternative Design ◽  
Fuel Supply ◽  
Small Engines ◽  
Supply Systems

Small and inexpensive jet engines are usually equipped with vaporizing fuel supply systems. This is in order to deliver low fuel flow-rates from relatively low-pressure fuel supply systems and the need for simple configuration. The difficulties associated with small engines are mainly during ignition or at high altitude re-lights, when the combustor is cold, air supply is poor, and fuel demand and pressure are low. Such conditions lead to poor atomization within the vaporizer resulting in very large droplets at its exit tip or even to a pool of liquid fuel within the combustor. Thus, there is no fuel vapor for ignition. Ignition is very difficult or even impossible under such conditions. Therefore, small engines are commonly equipped with dual fuel supply systems, either in the form of gaseous fuel for the ignition stage or with an additional higher-pressure supply line to the dedicated fuel nozzles for the purpose of ignition. Additional solutions involve the use of a large glow plug or high-energy pyrotechnic cartridges in the kilo-Joule range, to heat the combustor casing prior to ignition. The present work is concerned with the development of alternative and novel atomization systems, which would improve atomization at low pressures and consequently facilitate the ignition process, thus minimizing the need for supporting systems. The work refers to an alternative design for an existing vaporizer system of a small jet engine with 400 Nt of thrust. It focuses on an alternative design for the fuel injection within the vaporizer housing while maintaining all external dimensions and operating conditions unchanged. Three types of fuel nozzles were investigated: • a special impact atomizer, • a miniature pressure swirl atomizer, • a doublet atomizer involving two swirling nozzles (preliminary study only). Droplet size distribution under various nozzle pressure drops and air velocities were measured with Phase Doppler Particle Anemometry (PDPA) and global spray characteristics were obtained by photography. All modified atomization systems demonstrated improved performance and better atomization than the existing system. Initially, water was used as a liquid. At a later stage, the modified impact atomizer was tested and successful spark ignition was demonstrated.

scholarly journals The optimization of internal combustion engine oil change periods

2019 ◽  
Vol 26 (01) ◽  
pp. 157-162
Author(s):  
Davaasuren G ◽  
Gantulga G
Keyword(s):  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Operating Regime ◽  
Spare Parts ◽  
Operating Conditions ◽  
Engine Oil ◽  
Used Oil ◽  
Negative Effect

It is vitally important for vehicle users that are to study the operating regime that may negative effect to the operation of the engine, to reduce its effect, to maintain the engine's reliability in accordance with the specific operating conditions. Quality of lubrication is one of the main factors that are improving of reliability and operational efficiency for any machinery their spare parts. So this paper presents to optimize of oil change intervals and to determine of wear rating of spare parts by content of metal particles in the internal combustion engine used oil. Дотоод шаталтат хөдөлгүүрийн тос солих хугацааг оновчлох нь Хураангуй:  Машин ашиглагчдын хувьд тухайн хөдөлгүүрийн ажиллагаанд сөрөг нөлөө үзүүлэх  ашиглалтын горимыг судалж, түүний хор нөлөөг багасгах болон ашиглалтын өвөрмөц  нөхцөлд тохируулан хөдөлгүүрийн найдварт ажиллагааг ханган зөв, ашигтай ажиллуулах  чадвартай байх нь асар их ач холбогдолтой юм. Аливаа машин техник , тэдгээрийн агрегат,  зангилаа эд ангийн удаан эдлэхүй, найдвартай ажиллагааг хангах, ашиглалтын үр ашгийг  дээшлүүлэх гол хүчин зүйлүүдийн нэг нь тосолгооны чанар байдаг учраас дотоод шаталтат  хөдөлгүүрийн ашигласан тосон дахь металлын агууламжыг илрүүлж, эд ангийн элэгдлийн  явцыг тодорхойлон, тос солих хугацааг оновчлох асуудлыг судалгааны хүрээнд авч үзлээ.  Түлхүүр үг: Хөдөлгүүрийн ашигласан тосны шинжилгээ, металл хольц, тосны бохирдол,  тортог, элэгдлийн элементийн хязгаар 

Compressor Design for Multi-Point Operating Conditions of Turbocharged Gasoline Engines

2010 ◽  
Author(s):  
Tao Chen ◽  
Yangjun Zhang ◽  
Xinqian Zheng ◽  
Weilin Zhuge
Keyword(s):  
Internal Combustion Engines ◽  
Gasoline Engine ◽  
Design Method ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Combustion Engines ◽  
Gasoline Engines ◽  
Compressor Design ◽  
Operating Points ◽  
Load Conditions

Turbocharger compressor design is a major challenge for performance improvement of turbocharged internal combustion engines. This paper presents a multi-point design methodology for turbocharger centrifugal compressors. In this approach, several design operating condition points of turbocharger compressor are considered according to total engine system requirements, instead of one single operating point for traditional design method. Different compressor geometric parameters are selected and investigated at multi-point operating conditions for the flow-solutions of different design objectives. The method has been applied with success to a small centrifugal compressor design of a turbocharged gasoline engine. The results show that the consideration of several operating points is essential to improve the aerodynamic behavior for the whole working range. The isentropic efficiency has been increased by more than 5% at part-load conditions while maintaining the pressure ratio and flow range at full-load conditions of the gasoline engine.

Self-Adaptive Gas Sensor System Based on Operating Conditions Using Data Prediction

ACS Sensors ◽  
2021 ◽  
Author(s):  
Kyusung Kim ◽  
Phuwadej Pornaroontham ◽  
Pil Gyu Choi ◽  
Toshio Itoh ◽  
Yoshitake Masuda
Keyword(s):  
Gas Sensor ◽  
Operating Conditions ◽  
Sensor System ◽  
Data Prediction ◽  
Using Data ◽  
Self Adaptive

Analytical determination of the optimal clearance for the fatigue life of ball bearing under different load conditions

2021 ◽  
pp. 1-28
Author(s):  
Bin Fang ◽  
Jinhua Zhang
Keyword(s):  
Fatigue Life ◽  
Load Distribution ◽  
Life Prediction ◽  
Ball Bearing ◽  
Operating Conditions ◽  
Analytical Determination ◽  
Parameters Selection ◽  
Bearing Life ◽  
Structural Design Optimization ◽  
Load Conditions

Abstract In this paper, a comprehensive analytical model for the fatigue life prediction of ball bearing in various operating conditions is presented. Not only the internal clearance variations induced by the centrifugal expansion and assembly interference, but also ball inertia forces and ball-raceway separations are fully considered in theoretical modeling to achieve accurate life prediction of ball bearing. The model has been validated by comparison with the static results in previous literature. Based on this, the results of the load distribution and fatigue life versus the internal clearance of ball bearing under various operating conditions are studied. The results show that there is always an optimal clearance to maximize bearing fatigue life for the radial load or the combined load conditions, and the size of the optimal clearance for bearing life is determined by both the load conditions and rotating speeds to ensure the uniformity of the internal load distribution of the ball bearing. Therefore, the above theoretical and conclusions can be used in structural design optimization and assembly parameters selection of ball bearing to maximize the life characteristic.

scholarly journals New State Identification Method for Rotating Machinery under Variable Load Conditions Based on Hybrid Entropy Features and Joint Distribution Adaptation

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Xiaoming Xue ◽  
Nan Zhang ◽  
Suqun Cao ◽  
Wei Jiang ◽  
Jianzhong Zhou ◽  
...  
Keyword(s):  
Joint Distribution ◽  
Operating Conditions ◽  
Variable Load ◽  
Rolling Element Bearings ◽  
Time Frequency ◽  
Identification Method ◽  
State Identification ◽  
Rolling Element ◽  
Load Conditions ◽  
Testing Set

Fault identification under variable operating conditions is a task of great importance and challenge for equipment health management. However, when dealing with this kind of issue, traditional fault diagnosis methods based on the assumption of the distribution coherence of the training and testing set are no longer applicable. In this paper, a novel state identification method integrated by time-frequency decomposition, multi-information entropies, and joint distribution adaptation is proposed for rolling element bearings. At first, fast ensemble empirical mode decomposition was employed to decompose the vibration signals into a collection of intrinsic mode functions, aiming at obtaining the multiscale description of the original signals. Then, hybrid entropy features that can characterize the dynamic and complexity of time series in the local space, global space, and frequency domain were extracted from each intrinsic mode function. As for the training and testing set under different load conditions, all data was mapped into a reproducing space by joint distribution adaptation to reduce the distribution discrepancies between datasets, where the pseudolabels of the testing set and the final diagnostic results were obtained by the k-nearest neighbor algorithm. Finally, five cases with the training and testing set under variable load conditions were used to demonstrate the performance of the proposed method, and comparisons with some other diagnosis models combined with the same features and other dimensionality reduction methods were also discussed. The analysis results show that the proposed method can effectively recognize the multifaults of rolling element bearings under variable load conditions with higher accuracies and has sound practicability.

Alternative Design Approach for Multipass and Multi-Stream Plate Heat Exchangers for Use in Heat Recovery Systems

2006 ◽  
Vol 27 (6) ◽  
pp. 12-21 ◽  
Author(s):  
M. Picón-Núñez ◽  
G. Martínez-Rodríguez ◽  
J. L. López-Robles
Keyword(s):  
Heat Exchangers ◽  
Heat Recovery ◽  
Design Approach ◽  
Plate Heat ◽  
Alternative Design

Thermal Analysis Technique for Coolers Operating in Off and Low Load Conditions

2012 ◽  
Author(s):  
Thomas J. Muldoon
Keyword(s):  
Heat Exchanger ◽  
Power Plant ◽  
Heat Exchangers ◽  
Cooling Water ◽  
Control Valve ◽  
Operating Conditions ◽  
Outlet Temperature ◽  
Inlet Valve ◽  
Plant Personnel ◽  
Load Conditions

The most conservatively designed power plant heat exchangers are designed to meet a maximum heat load with minimum fluid temperature differences. When the input temperatures are less than design maximums, the cooler will usually be in a position of over performance. This relationship is especially true when the heat exchanger is a closed Component Cooling Water (CCW) heat exchanger with inlet fluid at ambient conditions. Maintaining a consistent cooling temperature is an important concern in the operation of a power plant. It is important that the cooling needs of the equipment such as the hydrogen coolers are maintained at a set temperature. Overcooling may not be of benefit to the equipment. The component which cools the service water with the local cooling water is a component cooling water heat exchanger (CCW). The two primary methods of controlling the heat rejection performance on these vessels is to throttling the tubeside flow to get a consistent shell outlet temperature with control valves or leave the tubeside flow constant and by-pass a portion of the shellside flow. Estimating the performance of the heat exchanger with given set of inlet conditions and a fixed design point can be accomplished using a the Number Transfer Units (NTU) method. Opening and closing the control valve is based on the estimated performance. This analysis can be used by power plant personnel to gauge the operation of these vessels over varying operating conditions. The analysis can also include the effect of different values of cleanliness and the extent of throttling. As a unit experiences fouling, additional flow is required to meet the thermal requirements. Depending upon the extent of fouling, the inlet valve will be either opened or closed. Plant personnel may observe the cooling water inlet temperature and the extent to which the inlet valve is open, and use that information to determine possible fouling and setup a maintenance schedule. The following analytical approach for evaluating low, critical, or off load conditions is important in the design and operation of these types of power plant heat exchangers, piping and control valve systems.

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