scholarly journals The experimental study on the electrical characteristics of flame applied to the measurement of rate of heat release in combustion

2017 ◽  
Author(s):  
TianYu Zhang ◽  
Ying Feng ◽  
ZhenNing Zhao
Keyword(s):  
Experimental Study ◽  
Heat Release ◽  
Electrical Characteristics ◽  
Rate Of Heat Release

scholarly journals Experimental Study on Dynamic Combustion Characteristics in Swirl-Stabilized Combustors

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1609
Author(s):  
Donghyun Hwang ◽  
Kyubok Ahn
Keyword(s):  
Experimental Study ◽  
Heat Release ◽  
Dynamic Pressure ◽  
Combustion Instability ◽  
Flame Structure ◽  
Pressure Sensors ◽  
Necessary Condition ◽  
Rayleigh Criterion ◽  
Pressure Oscillations ◽  
Geometric Conditions

An experimental study was performed to investigate the combustion instability characteristics of swirl-stabilized combustors. A premixed gas composed of ethylene and air was burned under various flow and geometric conditions. Experiments were conducted by changing the inlet mean velocity, equivalence ratio, swirler vane angle, and combustor length. Two dynamic pressure sensors, a hot-wire anemometer, and a photomultiplier tube were installed to detect the pressure oscillations, velocity perturbations, and heat release fluctuations in the inlet and combustion chambers, respectively. An ICCD camera was used to capture the time-averaged flame structure. The objective was to understand the relationship between combustion instability and the Rayleigh criterion/the flame structure. When combustion instability occurred, the pressure oscillations were in-phase with the heat release oscillations. Even if the Rayleigh criterion between the pressure and heat release oscillations was satisfied, stable combustion with low pressure fluctuations was possible. This was explained by analyzing the dynamic flow and combustion data. The root-mean-square value of the heat release fluctuations was observed to predict the combustion instability region better than that of the inlet velocity fluctuations. The bifurcation of the flame structure was a necessary condition for combustion instability in this combustor. The results shed new insight into combustion instability in swirl-stabilized combustors.

An Improved Rate of Heat Release Model for Modern High-Speed Diesel Engines

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Peter G. Dowell ◽  
Sam Akehurst ◽  
Richard D. Burke
Keyword(s):  
Heat Release ◽  
Diesel Engines ◽  
Engine Speed ◽  
Fuel Injection ◽  
Maximum Pressure ◽  
Injection Model ◽  
Wall Impingement ◽  
Small Set ◽  
Rate Of Heat Release ◽  
Engine System

To meet the increasingly stringent emissions standards, diesel engines need to include more active technologies with their associated control systems. Hardware-in-the-loop (HiL) approaches are becoming popular where the engine system is represented as a real-time capable model to allow development of the controller hardware and software without the need for the real engine system. This paper focusses on the engine model required in such approaches. A number of semi-physical, zero-dimensional combustion modeling techniques are enhanced and combined into a complete model, these include—ignition delay, premixed and diffusion combustion and wall impingement. In addition, a fuel injection model was used to provide fuel injection rate from solenoid energizing signals. The model was parameterized using a small set of experimental data from an engine dynamometer test facility and validated against a complete data set covering the full engine speed and torque range. The model was shown to characterize the rate of heat release (RoHR) well over the engine speed and load range. Critically, the wall impingement model improved R2 value for maximum RoHR from 0.89 to 0.96. This was reflected in the model's ability to match both pilot and main combustion phasing, and peak heat release rates derived from measured data. The model predicted indicated mean effective pressure and maximum pressure with R2 values of 0.99 across the engine map. The worst prediction was for the angle of maximum pressure which had an R2 of 0.74. The results demonstrate the predictive ability of the model, with only a small set of empirical data for training—this is a key advantage over conventional methods. The fuel injection model yielded good results for predicted injection quantity (R2 = 0.99) and enabled the use of the RoHR model without the need for measured rate of injection.

scholarly journals Experimental Study on the Valve Gap in the Gasoline Engine

2019 ◽  
Vol 256 ◽  
pp. 02011
Author(s):  
Fan Dong ◽  
Chong Lei ◽  
Xiao Yu Yang ◽  
Shao Feng Wang ◽  
Cong Ruan
Keyword(s):  
Experimental Study ◽  
Heat Release ◽  
Significant Influence ◽  
Normal State ◽  
Cylinder Head ◽  
Gasoline Engine ◽  
The Other ◽  
Gasoline Engines ◽  
Timing System

The influences of the installations of the camshaft support, and timing system and the heat release on the valve gap of the gasoline engine were analyzed in the present. The experiments were carried out on 50 4-cylinder 4-stroke gasoline engines, and the results indicate that to tighten the camshaft support has a great impact on valve gap, the indicated mean there was an obvious deformation in cylinder head after the camshaft support was tightened. The timing system also has a significant influence on the valve gap because it produces a downward force to the camshaft, leading to a smaller valve gap near the timing system and a bigger valve gap on the other side. It was also found that with the increase of temperature the valve gap was 0.1 mm larger than that in the normal state.

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