scholarly journals Passive Control of Base Pressure: A Review

2021 ◽  
Vol 11 (3) ◽  
pp. 1334
Author(s):  
Ambareen Khan ◽  
Parvathy Rajendran ◽  
Junior Sarjit Singh Sidhu
Keyword(s):  
Internal Combustion Engines ◽  
Passive Control ◽  
Control Device ◽  
Base Pressure ◽  
Combustion Engines ◽  
Favorable Pressure Gradient ◽  
Management Techniques ◽  
Base Drag ◽  
Present World ◽  
Control Management

In the present world, passive control finds application in various areas like flow over blunt projectiles, missiles, supersonic parallel diffusers (for cruise correction), the engine of jets, static testbeds of rockets, the ports of internal combustion engines, vernier rockets, and single expansion ramp nozzle (SERN) rockets. In this review, various passive control techniques to control the base pressure and regulate the drag force are discussed. In the study, papers ranging from subsonic, sonic, and supersonic flow are discussed. Different types of passive control management techniques like cavity, ribs, dimple, static cylinder, spikes, etc., are discussed in this review article. This study found that the passive control device can control the base pressure, resulting in an enhancement in the base pressure and reducing the base drag. Also, passive control is very efficient whenever there is a favorable pressure gradient at the nozzle exit.

Application of Nonlinear Vibration Absorbers to the Control of Piston Secondary Motion in Internal Combustion Engines

2015 ◽  
Author(s):  
Nader Dolatabadi ◽  
Stephanos Theodossiades ◽  
Steve J. Rothberg
Keyword(s):  
Internal Combustion Engines ◽  
Passive Control ◽  
Internal Combustion ◽  
Impact Behavior ◽  
Combustion Engines ◽  
Impulsive Behavior ◽  
Control Approach ◽  
Operation Conditions ◽  
Secondary Motion ◽  
Nonlinear Energy

The impulsive behavior of piston plays a key role in the Noise, Vibration and Harshness (NVH) of internal combustion engines. There have been several studies on the identification and quantification of piston impacting action under various operation conditions. In the current study, the dynamics of piston secondary motion are briefly explored, since this is fundamental to understanding the aggressive oscillations, energy loss and noise generation. Concepts of controlling piston secondary motion (and thus, impacts) are investigated and a new passive control approach is presented based on the nonlinear energy absorption of the highly transient oscillations. The effectiveness of this new method on the improvement of piston impact behavior is discussed, using a preliminary optimization exercise (with respect to engine excitation/speed, damping and stiffness of the nonlinear oscillator) that leads to the conceptual design of a nonlinear energy absorber.

DIESEL ENGINE OPERATION IN USE OF FUEL WITH ADDITIVES

2018 ◽  
pp. 18-24
Author(s):  
Petar Kazakov ◽  
Atanas Iliev ◽  
Emil Marinov
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Diesel Fuel ◽  
Internal Combustion Engines ◽  
Experimental Studies ◽  
Combustion Engines ◽  
Engine Operation ◽  
Factors Affecting ◽  
Operating Modes ◽  
Positive Effects

Over the decades, more attention has been paid to emissions from the means of transport and the use of different fuels and combustion fuels for the operation of internal combustion engines than on fuel consumption. This, in turn, enables research into products that are said to reduce fuel consumption. The report summarizes four studies of fuel-related innovation products. The studies covered by this report are conducted with diesel fuel and usually contain diesel fuel and three additives for it. Manufacturers of additives are based on already existing studies showing a 10-30% reduction in fuel consumption. Comparative experimental studies related to the use of commercially available diesel fuel with and without the use of additives have been performed in laboratory conditions. The studies were carried out on a stationary diesel engine СМД-17КН equipped with brake КИ1368В. Repeated results were recorded, but they did not confirm the significant positive effect of additives on specific fuel consumption. In some cases, the factors affecting errors in this type of research on the effectiveness of fuel additives for commercial purposes are considered. The reasons for the positive effects of such use of additives in certain engine operating modes are also clarified.

https://elibrary.ru/item.asp?id=44369782&pf=1

2020 ◽  
Author(s):  
QI CHEN ◽  
◽  
JINTAO SUN ◽  
JIANYU LIU ◽  
BAOMING ZHAO ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Internal Combustion Engines ◽  
Nonequilibrium Plasma ◽  
Combustible Mixture ◽  
Combustion Engines ◽  
Combustion Chemistry ◽  
Microwave Radio ◽  
Different Types ◽  
Gas Molecules ◽  
Ignition And Combustion

Plasma-assisted ignition and combustion, widely applied in gas turbines, scramjets, and internal combustion engines, has been considered as a promising technique in shortening ignition delay time, improving combustion energy efficiency, and reducing emission. Nonequilibrium plasma can excite the gas molecules to higher energy states, directly dissociate or ionize the molecules and, thereby, has the potential to produce reactive species at residence time and location in a combustible mixture and then to efficiently accelerate the overall pyrolysis, oxidation, and ignition. Previous studies have demonstrated the effectiveness of plasma-assisted combustion by using direct current, alternating currant, microwave, radio frequency, and pulsed nanosecond discharge (NSD). Due to the complicated interaction between plasma and combustion in different types of plasma, detailed plasma-combustion chemistry is still not well understood.

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