scholarly journals Research on the influence of LPG/CNG injector outlet nozzle diameter on uneven fuel dosage

Transport ◽  
2016 ◽  
Vol 33 (1) ◽  
pp. 186-196 ◽  
Author(s):  
Dariusz Szpica
Keyword(s):  
Research Methodology ◽  
Oxygen Sensor ◽  
Flow Characteristics ◽  
Nozzle Diameter ◽  
Mixture Composition ◽  
Outlet Nozzle ◽  
Minimum Value ◽  
Injector Nozzle ◽  
Flow Parameters

The paper presents an original flow research methodology in LPG/CNG injectors. When adapting alternative LPG systems of the IV generation, very often the injector nozzles are adapted individually to change the flow parameters. Hence, in the paper the author attempted to evaluate the influence of the injector nozzle diameter (min and max) on the uneven fuel dosage. The determined average throughputs were 0.0235–3.3683 mm2. The averaged difference in the unevenness reached 0.0419%, its minimum value is 0.0694 and the maximum is 0.7703, which can influence the correction of the mixture composition made through the oxygen sensor. Additionally, the flow characteristics of the injectors for both diameter variants have been presented, showing the necessity of inspecting the component after nozzle boring.

scholarly journals Developing a New Spatial Unit for Macroscopic Safety Evaluation Based on Traffic Density Homogeneity

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Chen Wang ◽  
Lin Liu ◽  
Chengcheng Xu
Keyword(s):  
Traffic Flow ◽  
Traffic Control ◽  
Flow Characteristics ◽  
Traffic Density ◽  
Minimization Method ◽  
Spatial Unit ◽  
Flow Parameters ◽  
Safety Knowledge ◽  
Traffic Operation ◽  
Crash Modeling

Macrolevel crash modeling has been extensively applied to investigate the safety effects of demographic, socioeconomic, and land use factors, in order to add safety knowledge into traffic planning and policy-making. In recent years, with the increasing attention to regional traffic management and control, the safety effects of macrolevel traffic flow parameters may also be of interest, in order to provide useful safety knowledge for regional traffic operation. In this paper, a new spatial unit was developed using a recursive half-cut partitioning procedure based on a normalized cut (NC) minimization method and traffic density homogeneity. Two Bayesian lognormal models with different conditional autoregressive (CAR) priors were applied to examine the safety effects of traffic flow characteristics at the NC level. It was found that safety effects of traffic flow exist at such macrolevel, indicating the necessity of considering safety for regional traffic control and management. Furthermore, traffic flow effects were also examined for another two spatial units: Traffic Analysis Zone (TAZ) and Census Tract (CT). It was found that ecological fallacy and atomic fallacy could exist without considering traffic flow parameters at those planning-based levels. In general, safety needs to be considered for regional traffic operation and the effects of traffic flow need to be considered for spatial crash modeling at various spatial levels.

Flow characteristics of misfired gas in the exhaust manifold of a spark ignition engine

2000 ◽  
Vol 214 (4) ◽  
pp. 373-381 ◽  
Author(s):  
Y Chung ◽  
H Kim ◽  
S Choi ◽  
C Bae
Keyword(s):  
Analytical Model ◽  
Oxygen Concentration ◽  
Oxygen Sensor ◽  
Flow Characteristics ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Exhaust Manifold ◽  
Cycle Simulation ◽  
Twin Peaks ◽  
Wide Range

Misfiring in spark ignition engines should be avoided, otherwise unburned fuel and oxygen are brought into the catalyst, and subsequent combustion greatly increases the temperature, possibly resulting in immediate damage to the catalyst. As a new concept of misfire detection method, the signal fluctuation of a wide-range oxygen sensor has been introduced to monitor the fluctuation of the oxygen concentration at the exhaust manifold confluence point. The current research aims to develop a tool that is capable of predicting the variation in oxygen concentration at the exhaust manifold confluence point, and to investigate the flow characteristics of the misfired gas in the exhaust manifold under misfiring conditions in a cylinder. The oxygen concentration at the confluence point could be predicted by comparing the gas flowrate from the misfiring cylinder with the total exhaust gas flowrate. The gas flowrates from each of the cylinders were calculated using a one-dimensional engine cycle simulation including a gas dynamic model of the intake and exhaust systems. The variation in oxygen concentration was also determined experimentally using a fast-response hydrocarbon analyser. The trend of the oxygen concentration fluctuation calculated by the analytical model was compared with the experimental results. The analytical model could duplicate the measured trend of the fluctuation of oxygen concentration at the confluence point, which was characterized by twin peaks for one misfiring. The twin peaks are mainly caused by the mixing of the misfired gas with the burned gas from normally operating cylinders. The effects of engine load and speed on the characteristics of the variation in oxygen concentration were also investigated analytically and experimentally.

The Sensitivity of Inner Nozzle Flow in Gasoline Direct Injection Injector to the Nozzle Geometry Parameters

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Xinhai Li ◽  
Yong Cheng ◽  
Xiaoyan Ma ◽  
Xue Yang
Keyword(s):  
Structural Parameters ◽  
Direct Injection ◽  
Large Diameter ◽  
Small Diameter ◽  
Flow Characteristics ◽  
Gasoline Direct Injection ◽  
Nozzle Geometry ◽  
Nozzle Flow ◽  
Nozzle Length ◽  
Injector Nozzle

The inner-flow of gasoline direct injection (GDI) injector nozzles plays an important role in the process of spray, and affects the mixture process in gasoline engine cylinder. The nozzle structure also affects the inner-flow of GDI injector. In order to obtain uniform performance of GDI injector, the size consistency of injector nozzle should be ensured. This paper researches the effect of nozzle length and diameter on the inner flow and analyzes the sensitivity of inner flow characteristics to these structural parameters. First, this paper reveals the process of inception, development, and saturated condition of cavitation phenomenon in injector nozzle. Second, the inner-nozzle flow characteristics are more sensitive to small diameter than large diameter under the short nozzle length, while the sensitivity of the inner-nozzle flow characteristics to large nozzle diameter becomes strong as the increase of the nozzle length. Finally, the influence of nozzle angle on the injection mass flow is studied, and the single nozzle fuel mass will increase as the decrease of nozzle angle α. And the sensitivity of inner-flow characteristic to nozzle angle becomes strong as the decrease of α.

Diesel Spray Rate-of-Momentum Measurement Uncertainties and Diagnostic Considerations

2014 ◽  
Author(s):  
Benjamin W. Knox ◽  
Michael J. Franze ◽  
Caroline L. Genzale
Keyword(s):  
Force Measurement ◽  
Control Volume ◽  
Flow Characteristics ◽  
Fuel Temperature ◽  
Integrated Electronics ◽  
Injector Nozzle ◽  
Fuel Delivery ◽  
Discharge Velocity ◽  
The Face ◽  
Measurement Uncertainties

Interpretation of combustion and emissions outcomes in diesel engines is often enhanced by accurate knowledge of the transient fuel delivery rate and flow characteristics of the injector nozzle. Important physical characteristics of these flows, including velocity profile and flow separation or cavitation effects, are difficult to measure directly, but can be characterized from a flow-averaged perspective through the measurement of nozzle flow coefficients, namely the discharge, velocity, and area contraction coefficients. Both the transient fuel mass flow rate and the flow-averaged nozzle coefficients can be found by measuring the mass and momentum flux of the fuel stream leaving the nozzle during injection through the application of an impingement technique, where fuel is sprayed onto the face of a transducer calibrated for force measurement in close proximity to the nozzle. While several published experiments have employed the spray impingement method to quantify rate-of-injection, the experimental setup and equipment selections vary widely and may contribute to disagreements in measured rate-of-injection. This paper identifies and provides estimates of measurement uncertainties that can arise when employing different experimental setups using the impingement method. It was observed that the impingement technique was sensitive to the design of the strike cap, specifically the contact area between the cap and transducer diaphragm, in addition to fuel temperature. Conversely, we observed that the impingement technique was relatively insensitive to angular and vertical misalignment, where the uncertainty can be estimated using control volume analysis. Transducer selection, specifically those with low acceleration sensitivity, high resonant frequency, and integrated electronics piezoelectric circuitry substantially reduce the noise in the measurement.

Fluid Flow Characteristics of a Confined Slot Jet Without or With a Target Surface

2005 ◽  
Author(s):  
L. K. Liu ◽  
C. J. Fang ◽  
M. C. Wu ◽  
C. Y. Lee ◽  
Y. H. Hung
Keyword(s):  
Reynolds Number ◽  
Fluid Flow ◽  
Fluid Velocity ◽  
Flow Characteristics ◽  
Target Surface ◽  
Streamwise Velocity ◽  
Separation Distance ◽  
Experimental Investigations ◽  
Flow Parameters ◽  
Fluid Flow Characteristics

A series of experimental investigations with a stringent measurement method on the fluid flow characteristics of slot jet without or with a target surface have been successfully conducted. From all the fluid velocity data measured in the present study, the experimental conditions have been verified to be spanwise-symmetrically maintained and the results have been achieved in a spanwise-symmetric form. Three types of jet configuration without or with target surface are investigated: (A) Confined Slot Jet without Target Surfaces – the fluid flow parameters studied in the present investigation is the jet Reynolds number (ReD). Its ranges are ReD=506-1517. (B) Confined Slot Jet with Smooth Surfaces – the fluid flow parameters studied in the present investigation include the ratio of jet separation distance (H) to nozzle width (W) and the jet Reynolds number (ReD). The ranges of the relevant parameters are H/W=2–10 and ReD=504–1526. (C) Confined Slot Jet with Extended Surfaces – the fluid flow parameters studied include the ratio of jet separation distance (H) to nozzle width (W), the Reynolds number (ReD) and the ratio of extended surface height (Hes) to nozzle width (W). Their ranges are H/W=3–10, Hes/W=0.74-3.40 and ReD=501–1547. The flow characteristics such as the local mean streamwise velocity distribution, mean streamwise velocity decay along jet centerline, local jet turbulence intensity distribution, and turbulence intensities along jet centerline have been presented and discussed in the study.

Study on Techniques for Online Measurement to Air and Pulverized Coal Mixture Flow Parameters of Coal-Fired Boiler in Power Plant

2005 ◽  
Author(s):  
Wei-Guo Pan ◽  
Yu Wang ◽  
Jiangmin Cao ◽  
Yunlong Zhou
Keyword(s):  
Power Plant ◽  
Flow Characteristics ◽  
Pulverized Coal ◽  
Point Location ◽  
Mixture Flow ◽  
Measuring Point ◽  
Flow Parameters ◽  
Coal Mixture ◽  
On Line ◽  
Precision System

Through analyzing the air and pulverized coal mixture flow characteristics of coal-fired boiler in power plant, it is put forward that measuring pulverized coal flow parameters is based on energy conservation theory and arrangement rule of measuring point location is for improving measurement precision. System for measuring temperature and velocity and concentration of air and pulverized coal mixture flow is developed, and some functions of on-line measuring air-pulverized coal mixture parameters are achieved. Adopting those efficient measuring methods are able to improve boiler operation’s safety and efficiency.

scholarly journals Proximity Effects on Characteristics of Flow around Three Inline Square Cylinders

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Waqas Sarwar Abbasi ◽  
Shams Ul Islam ◽  
Hamid Rahman
Keyword(s):  
Fluid Flow ◽  
Bluff Body ◽  
Flow Characteristics ◽  
Proximity Effects ◽  
Flow Parameters ◽  
Square Cylinders ◽  
Fluid Flow Characteristics ◽  
Bluff Body Flow ◽  
Boltzmann Method ◽  
Gap Spacing

This work presents the numerical investigations performed to study the proximity effects on fluid flow characteristics around three inline square cylinders using the lattice Boltzmann method. For this purpose the gap spacing (g) is systematically varied in the range 0.5 to 16 diameters of cylinder by keeping Reynolds number fixed at 200. Five different flow patterns are observed at different values of spacing: bluff body flow, gap trapped flow, irregular flow, alternate shedding, and modulated shedding. These patterns have a significant effect on flow induced forces and vortex shedding frequency. The spacing value g = 2 is found to be critical due to sudden changes in fluid flow characteristics. The flow parameters of first cylinder are found to be closer to single cylinder values but for middle and third cylinder the differences confirm the wake interference effect even at large values of spacing.

scholarly journals Investigation of droplet nucleation in CCS relevant systems: Progress in the design and testing of the mixture preparation device

2019 ◽  
Vol 213 ◽  
pp. 02092
Author(s):  
Václav Vinš ◽  
Miroslav Čenský ◽  
Jan Hrubý ◽  
Jiří Hykl
Keyword(s):  
Capillary Flow ◽  
Flow Characteristics ◽  
Capillary Tubes ◽  
Expansion Chamber ◽  
Pressure Transducers ◽  
Flow Parameters ◽  
Droplet Nucleation ◽  
Mixture Preparation ◽  
Inner Diameter ◽  
And Performance

The study presents progress in the development of mixture preparation device (MPD) representing an important part of the larger experimental setup intended for investigation of homogeneous droplet nucleation in CO2-rich systems. MPD allows for accurate adjustment of flow parameters, i.e. temperature, pressure, and flow rate, of CO2 in either superheated vapor or supercritical fluid phases and of other gas components such as argon or nitrogen. Through accurate settings of flow rates of individual components, the mixture composition can continuously be defined. MPD is going to be connected to the expansion chamber, where the droplet nucleation will experimentally be observed. In this work, CO2-branch, i.e. the core part of MPD, was modified and tested. Several components, e.g., pressure transducers and safety valve, had to be calibrated and adjusted to assure well-defined and safe operation. Most attention was paid to the design and performance of throttling capillary tubes installed in thermostatic bath, which define final flow parameters of CO2 coming from the CO2 branch. The flow characteristics of two capillary tubes with lengths of 7.8 and 4.0 m and inner diameter 0.1 mm were measured and compared to the predictions of a numerical model. The 1-D model of isothermal capillary flow was found to provide quite good agreement with the measured data.

scholarly journals The effect of nozzle diameter on the flow characteristics of air entrainment phenomenon in vertical plunging jets

2019 ◽  
Author(s):  
Warjito ◽  
Budiarso ◽  
Irvanda Adam Pramono ◽  
Mario Laurensus Samosir ◽  
Dendy Adanta
Keyword(s):  
Flow Characteristics ◽  
Air Entrainment ◽  
Nozzle Diameter ◽  
Plunging Jets
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