scholarly journals Review on the Effect of the Phenomenon of Cavitation in Combustion Efficiency and the Role of Biofuels as a Solution against Cavitation

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7265
Author(s):  
Ludovic Lamoot ◽  
Brady Manescau ◽  
Khaled Chetehouna ◽  
Nicolas Gascoin
Keyword(s):  
High Speed ◽  
High Performance ◽  
Research Work ◽  
Combustion Process ◽  
Energy Transition ◽  
Combustion Efficiency ◽  
Review Article ◽  
Cavitation Phenomenon ◽  
Heat Engines ◽  
High Speeds

Concerning the problem of wanting the performance of heat engines used in the automotive, aeronautics, and aerospace industries, researchers and engineers are working on various possibilities for improving combustion efficiency, including the reduction of gases such as CO, NOx, and SOx. Such improvements would also help reduce greenhouse gases. For this, research and development has focused on one factor that has a significant impact on the performance of these engines: the phenomenon of cavitation. In fact, most high-performance heat engines are fitted with a high-speed fuel supply system. These high speeds lead to the formation of the phenomenon of cavitation generating instabilities in the flow and subsequently causing disturbances in the combustion process and in the efficiency of the engine. In this review article, it is a question of making a state-of-the-art review on the various studies which have dealt with the characterization of the phenomenon of cavitation and addressing the possible means that can be put in place to reduce its effects. The bibliographic study was carried out based on five editors who are very involved in this theme. From the census carried out, it has been shown that there are many works which deal with the means of optimization that must be implemented in order to fight against the phenomenon of cavitation. Among these solutions, there is the optimization of the geometry of the injector in which the fuel flows and there is the type of fuel used. Indeed, it is shown that the use of a biofuel, which, by its higher viscosity, decreases the effects of cavitation. Most of these jobs are performed under cold fluidic conditions; however, there is little or no work that directly addresses the effect of cavitation on the combustion process. Consequently, this review article highlights the importance of carrying out research work, with the objective of characterizing the effect of cavitation on the combustion process and the need to use a biofuel as an inhibitor solution on the cavitation phenomenon and as a means of energy transition.

Characterization of Rotating Cavitation in a High Speed Inducer of Liquid Rocket Engine

2011 ◽  
Vol 320 ◽  
pp. 196-201
Author(s):  
Fei Tang ◽  
Li Jia Wen
Keyword(s):  
High Speed ◽  
High Performance ◽  
Rocket Engine ◽  
Liquid Rocket Engine ◽  
Blade Surface ◽  
Cavitation Phenomenon ◽  
Flow Fluctuations ◽  
Blade Cascade ◽  
Liquid Rocket

Rotating cavitation is one of the most important problems in the development of modern high performance rocket pump inducers. In this paper, a numerical simulation of rotating cavitation phenomenon in a 2D blade cascade of liquid rocket engine inducer was carried out using a mixture model based on Rayleigh-Plesset equation. The purpose is to investigate the characterization of rotating cavitation in a high speed inducer. The results show that when sub-synchronous rotating cavitation occurs, the speed for the length of the blade surface cavitation is lower than the speed frequency of rotation shaft with the same direction. The external aspect is that the pressure at the upstream of blades changes synchronous. Thus, the generation of sub-synchronous rotating cavitation is closely related to the changes of flow angel which caused by the flow fluctuations. Hence, elimination of the flow rate redistribution among the flow channel can effectively suppress the occurrence of this phenomenon.

The Role of High Performance Foil Bearings in Advanced, Oil-Free, High-Speed Motor Driven Compressors

2003 ◽  
Author(s):  
James F. Walton ◽  
Michael J. Tomaszewski ◽  
H. Heshmat
Keyword(s):  
High Speed ◽  
High Performance ◽  
Development Program ◽  
Foil Bearings ◽  
High Speeds ◽  
Start Up ◽  
Rolling Element ◽  
Temperature Capability ◽  
Full Speed ◽  
Bearing System

The demand for high power density, reliable, low maintenance, oil-free turbomachinery imposes significant demands on the bearing system. The full benefits of high speed, motor driven machines, for example are realized at speeds exceeding the capabilities of rolling element bearings. The high speeds, and requirement for oil-free operation in fuel cell applications also make conventional liquid lubricated bearings an undesirable alternative. The modern, oil-free foil bearing provides an excellent alternative, with its low power loss, damping for smooth high-speed operation and shock tolerance, elevated temperature capability and long maintenance free life. In this paper, the application of modern foil bearings to two different high-speed, oil-free compressors is discussed. In each application, foil bearings support a multi-component rotor operating at speeds above 70,000 RPM. Stable and reliable operation over the full speed range is demonstrated in each case. These applications also required low bearing start-up torque for compatibility with the torque characteristics of the integral motor. This work discusses the rotor bearing system design, the development program approach, and the results of testing to date.

Performance of Air-Lubricated Hydrodynamic Bearing Spindles for Laser Scanners

1991 ◽  
Vol 113 (3) ◽  
pp. 609-614 ◽  
Author(s):  
K. Tanaka ◽  
H. Muraki
Keyword(s):  
High Speed ◽  
High Performance ◽  
Experimental Results ◽  
Hydrodynamic Bearing ◽  
Vibration Resistance ◽  
High Speeds ◽  
Laser Printers ◽  
Laser Scanners

This paper reports on the performance of air-lubricated bearing spindles for high-speed laser scanners using newly developed bearings. Experimental results confirmed that these spindles have adequate performance including floating stability, endurance, vibration-resistance at high-speeds, and start-stop endurance for laser scanners. These spindles are already mass-produced and used in laser printers and digital color copiers, so their high performance and endurance are proven.

scholarly journals Nano-grating Assisted Light Absorption Enhancement for MSM-PDs Performance Improvement: An Updated Review

Photonics ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 539
Author(s):  
Narottam Das ◽  
Mohammad Nur-E-Alam ◽  
Alif Islam ◽  
Ain Zulaikha Maslihan Ain
Keyword(s):  
Light Absorption ◽  
Communication Systems ◽  
High Speed ◽  
High Performance ◽  
Optical Fiber Communication ◽  
Review Article ◽  
Absorption Enhancement ◽  
Fiber Communication ◽  
Communication Device ◽  
Primary Focus

The primary focus of this review article mainly emphasizes the light absorption enhancement for various nanostructured gratings assisted metal-semiconductor-metal photodetectors (MSM-PDs) that are so far proposed and developed for the improvement of light capturing performance. The MSM-PDs are considered as one of the key elements in the optical and high-speed communication systems for applications such as faster optical fiber communication systems, sensor networks, high-speed chip-to-chip interconnects, and high-speed sampling. The light absorption enhancement makes the MSM-PDs an ideal candidate due to their excellent performances in detection, especially in satisfying the high-speed or high-performance device requirements. The nano-grating assisted MSM-PDs are preordained to be decorous for many emerging and existing communication device applications. There have been a significant number of research works conducted on the implementation of nano-gratings, and still, more researches are ongoing to raise the performance of MSM-PDs particularly, in terms of enhancing the light absorption potentialities. This review article aims to provide the latest update on the exertion of nano-grating structures suitable for further developments in the light absorption enhancement of the MSM-PDs.

scholarly journals A Recent Progress of Spintronics Devices for Integrated Circuit Applications

2018 ◽  
Vol 8 (4) ◽  
pp. 44 ◽  
Author(s):  
Tetsuo Endoh ◽  
Hiroaki Honjo
Keyword(s):  
Integrated Circuit ◽  
High Speed ◽  
High Performance ◽  
Low Voltage ◽  
Review Article ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
The Other ◽  
Recent Advancement ◽  
Spintronics Device

Nonvolatile (NV) memory is a key element for future high-performance and low-power microelectronics. Among the proposed NV memories, spintronics-based ones are particularly attractive for applications, owing to their low-voltage and high-speed operation capability in addition to their high-endurance feature. There are three types of spintronics devices with different writing schemes: spin-transfer torque (STT), spin-orbit torque (SOT), and electric field (E-field) effect on magnetic anisotropy. The NV memories using STT have been studied and developed most actively and are about to enter into the market by major semiconductor foundry companies. On the other hand, a development of the NV memories using other writing schemes are now underway. In this review article, first, the recent advancement of the spintronics device using STT and the NV memories using them are reviewed. Next, spintronics devices using the other two writing schemes (SOT and E-field) are briefly reviewed, including issues to be addressed for the NV memories application.

scholarly journals DESIGN OF HIGH PERFORMANCE MULTIPLIERLESS LINEAR PHASE FINITE IMPULSE RESPONSE FILTERS

2017 ◽  
Vol 10 (13) ◽  
pp. 66
Author(s):  
A Aparna ◽  
T Vigneswaran
Keyword(s):  
Low Power ◽  
Impulse Response ◽  
High Speed ◽  
High Performance ◽  
Finite Impulse Response ◽  
Research Work ◽  
Digital Signal ◽  
Fir Filter ◽  
Pass Filter ◽  
Finite Impulse Response Filters

This research work proposes the finite impulse response (FIR) filters design using distributed arithmetic architecture optimized for field programmable gate array. To implement computationally efficient, low power, high-speed FIR filter a two-dimensional fully pipelined structure is used. The FIR filter is dynamically reconfigured to realize low pass and high pass filter by changing the filter coefficients. The FIR filter is most fundamental components in digital signal processing for high-speed application. The aim of this research work is to design multiplier-less FIR filter for the requirements of low power and high speed various embedded applications. 

scholarly journals Evaluation of Meshed Reference Planes for High Performance Applications

2000 ◽  
Vol 22 (3) ◽  
pp. 175-187 ◽  
Author(s):  
N. D. Codreanu ◽  
P. Svasta ◽  
V. Golumbeanu ◽  
L. Gál
Keyword(s):  
Integrated Circuits ◽  
High Frequency ◽  
High Speed ◽  
High Performance ◽  
Network Analyzer ◽  
High Frequencies ◽  
High Speeds ◽  
University Of Budapest ◽  
Very High Frequencies ◽  
Very High

The actual generations of integrated circuits are characterized, inter alia, by very high frequencies or very high speeds. The dramatic evolution ofthe semiconductor's technology establishes a greater “pressure” to the design and the manufacturing of the passive interconnection structure from PCB/MCM electronic modules. In these conditions the reference planes (power and ground planes) have a more and more important contribution. The paper intents to present the effect of different configuration reference planes on the characteristics of the high speed/high frequency interconnection lines. The first part deals with modeling and simulation of usual practical interconnection geometries. A computer modeling of meshed structures was realized and Spice models for a good compatibility with circuit simulators were obtained.S-,Y-,Z- parameters and radiation patterns were calculated, too. The second part contains measurements made by a vector network analyzer as regards to different practical configurations manufactured at Technical University of Budapest.

scholarly journals Research status and development trend of ceramifiable silicone rubber composites: a brief review

2021 ◽  
Author(s):  
Jianhua Li
Keyword(s):  
Mechanical Properties ◽  
Silicone Rubber ◽  
High Speed ◽  
High Performance ◽  
Degradation Mechanism ◽  
Research Work ◽  
Development Trend ◽  
High Tech ◽  
Reaction Products ◽  
Rubber Composites

Abstract Ceramifiable silicone rubber composites (CSR) are one of the most important industrially produced elastic technical materials. At present, there is a strong demand for CSR in the high-tech fields of high-speed rail, nuclear power, rocket and aerospace, which are still to be met. Many scholars have committed to the research work of improving the thermal stability, flame retardant, mechanical properties by changing the silicone rubber (SR) matrixes and filler, tremendous advances in CSR have been made for over the last decades where CSR intended for the high technology fields has evolved through different generations. In summary, the first-generation research is based on matrix reaction, the second-generation research is on reaction products, and the third-generation research is on fillers effects. In this review, the evolution of CSR and the synthesis routes, reaction mechanism, and degradation mechanism are introduced and analysed; fillers, various types of CSR based composites as well as the flame retardancy and mechanical properties are reviewed. Finally, the problems of developing high-performance CSRs are proposed and discussed. This review provides a theoretical basis and supporting data for the application of high-performance CSR, as well as provides details on the fire prevention mechanism of CSR.

scholarly journals Ancient Vedic Multiplication Based Optimized High Speed Arithmetic Logic

2014 ◽  
Vol 3 (03) ◽  
pp. 01-06
Author(s):  
Mrs. Leena Rathi
Keyword(s):  
Integrated Circuit ◽  
High Speed ◽  
Research Work ◽  
Processing Unit ◽  
Central Processing ◽  
High Speeds ◽  
Quartus Ii ◽  
Hardware Description ◽  
Digital Processor ◽  
Very High

Here, we deal with most effective Vedic multiplication method dependent 4*4 bit arithmetic logic unit having high speed. In this paper, we will perform ALU operations. ALU is a development of research work that has been done for years so we have chosen this topic. Normally ALU is a heart of digital processor, central processing unit, microprocessor and micro controller. Every digital domain based technology has to depend on the performance of ALU. Hence, there is a necessity of ALU which generates high speeds which depends on the speed of multiplier. Therefore, we go for designing a 4-bit multiplier. To generate high speeds, multiplier is employed which is one of the important blocks of the hardware unit and also an important initiation of delay in the path. We have studied many algorithms for multiplication technique but research says that Vedic multiplication is most effective of all in terms of speed. The algorithm contains 16 sutra, out of which we are employing URDHVA TIRYAKBHYAM and the code is written in Very High Speed Integrated Circuit Hardware Description. Our supporting synthesizing and simulating tools are Xilinx ISE9.2i and model sim-altra6.3g-pi (Quartus II) respectively. At last, we will compare 4-bit ALU with 4-bit Array ALU.     

scholarly journals Measurement of Rigidity Change of Preload Switching Spindle

2012 ◽  
Vol 6 (2) ◽  
pp. 175-179 ◽  
Author(s):  
Taku Yamazaki ◽  
◽  
Atsushi Matsubara ◽  
Shinya Ikenaga ◽  
Keyword(s):  
High Speed ◽  
High Performance ◽  
High Rigidity ◽  
High Speeds ◽  
Loading Device ◽  
Magnetic Loading ◽  
Simulation Results ◽  
Load Displacement ◽  
Low Speeds ◽  
Relationship Of

High performance milling spindles with high rigidity and high speed are required for high productive machining. A preload switching spindle has been designed to obtain high rigidity at low speeds while avoiding bearing burn at high speeds. In this report, the load-displacement relationship of a preload switching spindle is measured with a non-contact magnetic loading device. Measurement and simulation results are compared to clarify the rigidity change by preload switching.

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