Effect of Preheated Fuel on Mixture Formation of Biodiesel Spray

2013 ◽  
Vol 393 ◽  
pp. 493-498 ◽  
Author(s):  
Amir Khalid ◽  
Christian Yohan M. Jaat ◽  
Izzuddin Zaman ◽  
B. Manshoor ◽  
M.F.M. Ali

The key issue in using vegetable oil-based fuels is oxidation stability, stoichiometric point, bio-fuel composition, antioxidants on the degradation and viscosity thus influences to the different spray atomization and fuel air mixing characteristics. Purpose of this study is to investigate the effect of preheated biodiesel on fuel properties, spray characteristics and mixture formation. The detail behavior of mixture formation was investigated using the direct photography system with a digital color camera. This method can capture spray evaporation, spray length and mixture formation clearly with real images. Increased preheated fuel is found to enhance the spray penetration, resulting in increased the spray area and enhanced fuel-air premixing.

2013 ◽  
Vol 465-466 ◽  
pp. 296-301 ◽  
Author(s):  
Mohamad Farid Sies ◽  
Norrizal Mustaffa ◽  
Hanis Zakaria ◽  
Hamidon bin Salleh ◽  
Bukhari Manshoor ◽  
...  

This paper reviews the effects of premix fluids between biodiesel, air, and water for external combustion especially open burner. During burning process, biodiesel combustion involves the fuel-air mixing characteristic such as oxidation stability, stoichiometric point, bio-fuel composition, antioxidants and viscosity that influences more NOx emissions than diesel fuel. The strategies to reduce NOx emission are acquired with water additional in biodiesel fuel mixing during early stage of burning process. The method to mix biodiesel-water with injector was acquired in burner system. A vast majority of author reported that the variation in mixing of blending biodiesel ratio and water was found to enhance the burning process and mixture formation thus predominantly reducing the NOx emissions.


2020 ◽  
Vol 40 (04) ◽  
Author(s):  
VO TAN CHAU

The diversity of alternative fuels and the corresponding variation in their physical and chemical properties, coupled with simultaneous changes in advanced techniques for CI-engine, needed to improve engine efficiency and emissions. Hydrotreated Vegetable Oil (HVO), seen as a promising substitution for petrol-diesel, and diesel fuel (mixed of 7% palm-biodiesel or B7) were analyzed on fuel properties. Then, the influence of these fuel properties on spray characteristics in constant volume combustion chamber were evaluated under conditions of single hole injector of 200m diameter, injection pressure of 100MPa, constant back pressure of 4.0MPa and energizing time of 2.5ms. The results show that HVO had smaller in viscosity (18.48%), density (5.52%), sulfur content, distillation under T50, T90 and higher in derived cetane index (27.2%), heating value (2.2%), respectively, compared to diesel. Spray characteristics of HVO had the same propensity with diesel fuel. HVO revealed a slightly shorter in penetration length (5%) during fully developed zone, a larger spray cone angle (from 0.2 to 1.1 degree wider in quasi-steady state). Both fuels had a similar maximum spray velocity reaching at 5mm to 10mm from nozzle orifice. Also observed was an increase in spray volume of HVO.


2021 ◽  
pp. 146808742098776
Author(s):  
Nikhil Sharma ◽  
Avinash Kumar Agarwal

Renewable fuels are continuously being refined/ upgraded for automotive applications to reduce dependence on conventional fossil fuels. However, optimized use of these renewable fuels in existing and new engines/ vehicles requires comprehensive characterization and understanding of spray atomization and fuel-air mixture formation processes. Spray atomization and mixture formation depends on fuel injection pressure (FIP), fuel injection quantity and ambient conditions. This study is aimed at exploring microscopic spray characteristics of ethanol and methanol blended gasoline for automotive applications, particularly in direct injection Spark Ignition (DISI) engines. Phase Doppler interferometer (PDI) technique was used for comparative microscopic spray characterization in a constant volume spray chamber (CVSC) at ambient pressure condition, to evaluated spray droplet size-velocity distributions and joint probability density function (JPDF) of different test fuels. In this study, two gasohol mixtures [15% v/v ethanol and methanol blended with 85% v/v gasoline] and baseline gasoline were experimentally evaluated for comparing spray droplet size-velocity distributions at two different FIPs of 80 and 160 bars, at two different fuel injection quantities of 12 and 28 mg/injection, which are typical representative conditions for a DISI engines. The results from this experimental investigation are valuable for automotive and fuel industries, and spray community, which are continuously upgrading renewable and oxygenated fuels and engine technologies for efficiency improvement and emission reduction.


2014 ◽  
Vol 3 (10) ◽  
pp. 3419
Author(s):  
Mohan Reddy Nalabolu* ◽  
Varaprasad Bobbarala ◽  
Mahesh Kandula

At the present moment worldwide waning fossil fuel resources as well as the tendency for developing new renewable biofuels have shifted the interest of the society towards finding novel alternative fuel sources. Biofuels have been put forward as one of a range of alternatives with lower emissions and a higher degree of fuel security and gives potential opportunities for rural and regional communities. Biodiesel has a great potential as an alternative diesel fuel. In this work, biodiesel was prepared from waste cooking oil it was converted into biodiesel through single step transesterification. Methanol with Potassium hydroxide as a catalyst was used for the transesterification process. The biodiesel was characterized by its fuel properties including acid value, cloud and pour points, water content, sediments, oxidation stability, carbon residue, flash point, kinematic viscosity, density according to IS: 15607-05 standards. The viscosity of the waste cooking oil biodiesel was found to be 4.05 mm2/sec at 400C. Flash point was found to be 1280C, water and sediment was 236mg/kg, 0 % respectively, carbon residue was 0.017%, total acid value was 0.2 mgKOH/g, cloud point was 40C and pour point was 120C. The results showed that one step transesterification was better and resulted in higher yield and better fuel properties. The research demonstrated that biodiesel obtained under optimum conditions from waste cooking oil was of good quality and could be used as a diesel fuel.


2013 ◽  
Vol 465-466 ◽  
pp. 260-264 ◽  
Author(s):  
Hanis Zakaria ◽  
Amir Khalid ◽  
Mohamad Farid Sies ◽  
Norrizal Mustaffa

Biofuels based on vegetable oils offer the advantage being a sustainable and environmentally attractive alternative to conventional petroleum based fuel. The key issue in using vegetable oil-based fuels is oxidation stability, stoichiometric point, bio-fuel composition, antioxidants on the degradation and much oxygen with comparing to diesel gas oil. This provides a critical review of current understanding of main factor in storage method which affecting the biodiesel properties and characteristics. In the quest for fulfill the industry specifications standard; the fuel should be stored in a clean, dry and dark environment. Water and sediment contamination are basically housekeeping issues for biodiesel. Degradation by oxidation yields products that may compromise fuel properties, impair fuel quality and engine performance. The effect of storage method on the fuel properties and burning process in biodiesel fuel combustion will strongly affects the exhaust emissions.


Author(s):  
Xiaoyu Wang ◽  
Tinghao Jia ◽  
Lun Pan ◽  
Qing Liu ◽  
Yunming Fang ◽  
...  

AbstractThe development of advanced air transportation has raised new demands for high-performance liquid hydrocarbon fuels. However, the measurement of fuel properties is time-consuming, cost-intensive, and limited to the operating conditions. The physicochemical properties of aerospace fuels are directly influenced by chemical composition. Thus, a thorough investigation should be conducted on the inherent relationship between fuel properties and composition for the design and synthesis of high-grade fuels and the prediction of fuel properties in the future. This work summarized the effects of fuel composition and hydrocarbon molecular structure on the fuel physicochemical properties, including density, net heat of combustion (NHOC), low-temperature fluidity (viscosity and freezing point), flash point, and thermal-oxidative stability. Several correlations and predictions of fuel properties from chemical composition were reviewed. Additionally, we correlated the fuel properties with hydrogen/carbon molar ratios (nH/C) and molecular weight (M). The results from the least-square method implicate that the coupling of H/C molar ratio and M is suitable for the estimation of density, NHOC, viscosity and effectiveness for the design, manufacture, and evaluation of aviation hydrocarbon fuels.


Author(s):  
Wenliang Qi ◽  
Zilong Yang ◽  
Pingjian Ming ◽  
Wenping Zhang ◽  
Ming Jia ◽  
...  

An improved droplet breakup model coupled with the effect of turbulence flow within the nozzle was implemented into the general transport equation analysis code to describe the flame lift-off length and predict the soot distribution. This model was first validated by the non-evaporating and evaporating spray experimental data. The computational results demonstrate that the breakup model is capable of predicted spray penetration and liquid length with reasonable accuracy. The inclusion of turbulence enhanced the breakup model, increased the droplet breakup rate, decreased spray penetration for about 6–12% compared to the results of Kelvin-Helmholtz Rayleigh-Taylor (KH-RT) breakup model. Then, the model was applied to investigate the influence of ambient density, temperature, oxygen concentration and injection pressure on the flame lift-off length under typical diesel combustion conditions. The predictions showed good agreement with the experimental data. The result also indicated that the turbulence inside the nozzle strengthen the rate of breakup, resulting in more smaller droplets, leading to high evaporation rate and smaller vapour penetration lengths, thus decreases the lift-off length about 8%. Finally, the model was used to explore the soot distribution. The overall trend of soot with the variations in injection pressure was well reproduced by the breakup model. It was found that the droplet with faster velocity under high injection pressure, this could lead to larger lift-off length, which will play a significant role for the fuel–air mixing process and thus cause a decrease in soot in the fuel jet. Results further indicated that the turbulence term can decrease the soot mass about 5–9% by improved the droplet breakup process.


2019 ◽  
Vol 21 (9) ◽  
pp. 1662-1677 ◽  
Author(s):  
Xinyi Zhou ◽  
Tie Li ◽  
Yijie Wei ◽  
Ning Wang

Scaled model experiments can greatly reduce the cost, time and energy consumption in diesel engine development, and the similarity of spray characteristics has a primary effect on the overall scaling results of engine performance and pollutant emissions. However, although so far the similarity of spray characteristics under the non-evaporating condition has been studied to some extent, researches on scaling the evaporating sprays are still absent. The maximum liquid penetration length has a close relationship with the spray evaporation processes and is a key parameter in the design of diesel engine spray combustion system. In this article, the similarity of maximum liquid penetration length is theoretically derived based on the hypotheses that the spray evaporation processes in modern high-pressure common rail diesel engines are fuel–air mixing controlled and local interphase transport controlled, respectively. After verifying that the fuel injection rates are perfectly scaled, the similarity of maximum liquid penetration length in evaporating sprays is studied for three scaling laws using two nozzles with hole diameter of 0.11 and 0.14 mm through the high-speed diffused back-illumination method. Under the test conditions of different fuel injection pressures, ambient temperatures and densities, the lift-off law and speed law lead to a slightly increased maximum liquid penetration length, while the pressure law can well scale the maximum liquid penetration length. The experimental results are consistent with the theoretical analyses based on the hypothesis that the spray evaporation processes are fuel–air mixing controlled, indicating that the local interphase transports of energy, momentum and mass on droplet surface are not rate-controlled steps with respect to spray evaporation processes.


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