Atomization of fuel mixtures

The combustion process of a coal/oil slurry begins by atomization of the slurry. This project is a presentation of experimental system and results on atomization of coal/oil(COM) and coal/methanol mixtures with a twin-fluid and a wheel atomizer. The slurries are consisted of coal/methanol and coal/oil mixtures with two different concentrations and two coal particile sizes. The volume median diameters of the coal particles were 45 and 130 microns. The oil was No. 2 diesel oil. The droplet size was determined by photographing the spray and the photographs were analyzed to determine droplet size and distribution. The results show that the inclusion of particles in the liquid(both methanol and diesel oil) does not appreciably affect the atomized droplet size. The tendency is for the slurry droplets to be somewhat smaller than the droplets atomized with the pure liquid.     

基于PLC的柴油机重油动态乳化过程控制系统

根据船舶柴油机重油动态乳化过程的特点,设计了将PLC控制的方法应用于重油动态乳化过程的控制系统,介绍了系统的工作流程、功能特点以及系统硬件和软件设计,并给出了部分实验核心程序。实验结果表明,该系统对掺水率的控制精度可达1%以上,燃油消耗率平均降低7.8%。     

The effect of water emulsified fuel on a motorway-bus diesel engine

In this study, the combustion characteristics and durability of a diesel engine using emulsified fuel was investigated. Water was used in oil type emulsified fuel. In order to understand the effect of emulsified fuel in a wide range of engine running conditions, D-13 mode was selected as a test condition, and a durability test was included to understand the long-term effect of water. Combustion pressure in a cylinder, exhaust emissions, specific fuel consumption, sound level and maximum torque were measured. NOx and PM were simultaneously reduced and the specific fuel consumption was increased and decreased at low and high loads, respectively. There was no trouble and any damage on the parts of the cylinder during a 500 hour durability test.     

一种全自动柴油乳化柜的设计与研究

针对目前乳化油应用中遇到的问题，采用机械乳化原理和可编程逻辑控制器（PLC）控制技术，设计出了一种基于PLC控制的全自动柴油乳化柜。在不改变柴油机结构参数的前提下，在6300ZC型柴油机上进行了台试实验。试验结果证明，该装置乳化后的乳化油微粒能较好地满足柴油机燃烧要求，在中高负荷时，平均节油率达9．4％，且碳烟与NOx排放下降明显。     

Atomization characteristics in pneumatic counterfiowing internal mixing nozzle

In an effort to illustrate the global variation of SMD (Sauter mean diameter, orD ₃₂) and AMD (Arithmetic mean diameter, orD ₁₀) at five axial downstream locations (i. e., at Z=30, 50, 80, 120, and 170 mm) under the different experimental conditions, the radial coordinate is normalized by the spray half-width. Experimental data to analyze the atomization characteristics concerning with an internal mixing type have been obtained using a PDPA (Phase Doppler Particle Analyzer). The air injection pressure was varied from 40 kPa to 120 kPa. In this study, counterfiowing internal mixing nozzles manufactured at an angle of l5^o with axi-symmetric tangential-drilled four holes have been considered. By comparing the results, it is clearly possible to discern the effects of increasing air pressure, suggesting that the disintegration process is enhanced and finer spray droplets can be obtained under higher air assist. The variations inD ₃₂ are attributed to the characteristic feature of internal mixing nozzle in which the droplets are preferentially ejected downward with strong axial momentum, and dispersed with the larger droplets which are detected in the spray centerline at the near stations and smaller ones are generated due to further subsequent breakup by higher shear stresses at farther axial locations. The poor atomization around the centre close to the nozzle exit is attributed to the fact that the relatively lower rates of spherical particles are detected and these drops are not subject to instantaneous breakup in spite of the strong axial momentum. However, substantial increases in SMD from the central part toward the edge of the spray as they go farther downstream are mainly due to the fact that the relative velocity of droplet is too low to cause any subsequent disintegration.     

Numerical prediction of characteristics of ash deposition in heavy fuel oil heat recovery steam generator

Resolving ash-related problems such as fouling and slagging is crucial to the operation of a heat recovery steam generator (HRSG) in a power plant using heavy fuel oil (HFO). This paper presents numerical predictions of ash particle deposition using a model implemented with CFD code. The deposition model considers the force of gravity, elastic rebound, and adhesion forces acting at the moment of ash particle impact, which determine if the particle bounces off or stays on the surface and accumulates into a deposit. The 2D simulation results showed that ash deposition depends significantly on the particle size and velocity. The normal gravity force is a significant parameter that determines the position of deposition. The simulation results for ash deposition in an HFO-HRSG showed that ash deposits are highest (~34%) in the first and second rows, where the particles hit first, after which deposition decreases. However, ash deposits in the internal array increase again in the rear rows because rebounding particles decelerate and are deposited because of gravity, as confirmed by observations of actual deposit formation.     

Global characteristics of low-flow-rate aviation fuel sprays by image processing

Journal of Mechanical Science and Technology - Spray characteristics should be measured to understand fluid atomization. In this study, we investigated the atomization of kerosene fuel with...     

Atomization characteristics of intermittent multi-hole diesel spray using time-resolved PDPA data

The intermittent spray characteristics of a multi-hole diesel nozzle with a 2-spring nozzle holder were investigated experimentally. Without changing the total orifice exit area, the hole number of the multi-hole nozzle varied from 3 (d_n=0.42 mm) to 5 (d_n=0.32mm). The time-resolved droplet diameters of the spray including the SMD (Sauter mean diameter) and the AMD (arithmetic mean diameter), injected intermittently from the multi-hole nozzles into still ambient air, were measured by using a 2-D PDPA (phase Doppler particle analyzer). The 5-hole nozzle spray shows the smaller spray cone angle, the decreased SMD distributions and the small difference between the SMD and the AMD, compared with that of the 3-hole nozzle spray. From the SMD distributions with the radial distance, the spray structure can be classified into the three regions : (a) the inner region showing the high SMD distribution; (b) the mixing flow region where the shear flow structure would be constructed; and (c) the outer region formed through the disintegration processes of the spray inner region and composed of fine droplets. Through the SMD distributions along the spray centerline, it reveals that the SMD decreases rapidly after showing the maximum value in the vicinity of the nozzle tip. The SMD remains the constant value near the Z/d_n=166 and 156.3 for the 3-hole and 5-hole nozzles, which illustrate that the disintegration processes of the 5-hole nozzle spray proceed more rapidly than that of the 3-hole nozzle spray.     

基于PLC的柴油动态乳化装置设计及试验研究

根据柴油动态乳化技术,设计了一种基于可编程序控制器的油柜式柴油动态乳化装置.该装置以PLC为核心控制元件来采集柴油、水和乳化剂流量信号,并对信号进行分析处理,实现柴油的动态乳化.通过在6300ZC船舶柴油机上的实验表明,该装置工作可靠,操作简单,平均节油率达7.6%,NOx和烟度的排放量分别降低了23%和30%.     

A technique to measure fuel oil viscosity in a fuel power plant

The viscosity measurement and control of fuel oil in power plants is very important for a proper combustion. However, the conventional viscometers are only reliable for a short period of time. This paper proposes an on-line analytic viscosity evaluation based on energy balance applied to a piece of tube entering the fuel oil main heater and a new control strategy for temperature control. This analytic evaluation utilizes a set of temperature versus viscosity graphs were defined during years of analysis of fuel oil in Mexican power plants. Also the temperature set-point for the fuel oil main heater output is obtained by interpolating in the corresponding graph. Validation tests of the proposed analytic equations were carried out in the Tuxpan power plant in Veracruz, Mexico.     

Static characteristics of conical hydrodynamic bearings lubricated by turbine oil

Formulas for the static characteristics of conical hydrodynamic bearings of three types are considered, with variable thermophysical properties of the lubricant.     

高温高压燃滑油综合试验台测控系统设计

介绍了高温高压燃滑油综合试验台计算机控制系统的结构、特点及功能.详细分析了测控系统的软件实现,利用VB语言实现了相应程序的编制和人机界面的制作.高温高压燃滑油综合试验台适用于航空发动机燃滑油散热器的研究.该系统已投入实际运行,并取得良好效果.     

16V240ZJB型柴油机机油乳化的原因及处理办法

对16V240ZJB型柴油机机油乳化现象及可能产生的危害进行了描述,并对该型柴油机机油乳化的原因进行分析,找出切实可行的处理办法.     

Atomization characteristics and prediction accuracy of LISA-DDB model for gasoline direct injection spray

In this paper, the spray atomization characteristics of a gasoline direct-injection injector were investigated experimentally and numerically. To visualize the developing spray process, a laser sheet method with a Nd :YAG laser was utilized. The microscopic atomization characteristics such as the droplet size and velocity distribution were also obtained by using a phase Doppler particle analyzer system at the 5 MPa of injection pressure. With the experiments, the calculations of spray atomization were conducted by using the KIVA code with the LISA-DDB breakup model. Based on the agreement with the experimental results, the prediction accuracy of LISA-DDB breakup model was investigated in terms of the spray shapes, spray tip penetration, SMD distribution, and axial mean velocity. The results of this study provides the macroscopic and microscopic characteristics of the spray atomization, and prediction accuracy of the LISA-DDB model.     

重油掺水乳化燃烧技术在轧钢加热炉上的应用

面对当前燃油紧张的局面，采取有效措施降低油耗势在必行。重油掺水乳化燃烧技术在轧钢加热炉上的应用取得了良好的经济效益和社会效益。     

风油调节系统和燃油加热系统的设计

注汽锅炉是油田稠油热采工艺中的重要设备,本文针对辽河油田总机械厂生产的50t/h油田注汽锅炉重点论述了50T燃油注汽锅炉风油调节系统和燃油加热系统的设计原理和控制方法,并标明了系统结构框图.     

Atomization characteristics of a double impinging F-O-O-F type injector with four streams for liquid rockets

This paper presents atomization characteristics of a double impinging F-O-O-F type injector with four streams. A phase Doppler particle analyzer was employed to measure the droplet-size and water was used as the inert simulant liquid instead of reactive propellant liquids. The droplet mean diameter (SMD) and size distribution were measured to investigate the effects of the momentum ratio and pressure drop variations. This experimental results can be used during the preliminary design stage of a impinging stream type injector for liquid rockets.