Spray Length Research Articles

Development of a flexible electronic control unit for seamless integration of machine vision to CAN-enabled boom sprayers for spot application technology

This research work aimed to develop an Electronic Control Unit (ECU) to establish a flexible bridge between machine vision and boom sprayer to control nozzles individually for pesticide spot application based on the Controller Area Network (CAN). The ECU consisted of two electronic entities. The first used UART protocol to parse machine vision messages, detect pest areas, and convert them into binary arrays for nozzle activation. The second received these arrays and generated nozzle controller CAN frames which were broadcast to control the sprayer nozzles on the implement bus. The ECU was tested in four scenarios involving combinations of three machine vision systems and two nozzle systems. The lab tests confirmed, assuming accurate detections, the ECU successfully sent spray commands to all targets across various camera-nozzle ratios. However, at specific ratios (1:3 and 1:6), some nozzles opened in unintended patterns. In the fourth scenario conducted in the field at a 1:2 ratio, all targets were sprayed regardless of their dimensions and distribution in the field. In this scenario, the sprayer operated at speeds of 3.22 km/h, 6.44 km/h, and 9.66 km/h, demonstrating real-time spraying with 55° angled nozzles, where the ECU sent CAN messages every 10ms and issued 400 ms spray commands upon detection, achieving a minimum spray length of 345 mm per detection.

The Beneficial Effects of Soluble Silicon Fertilizer in Dendrobium Orchids: Silicon-Augmented Resistance against Damage by Insect Pests and Fungal Pathogens.

The effects of soluble silicon fertilization on monocots and dicots have been widely studied. However, little is known regarding its effects on protecting epiphytes against insect and fungal pests. The efficacy of silicon fertilizer to reduce damage by thrips pest complexes, namely: Thrips palmi Karny, Frankliniella occidentalis Pergande, Chaetanaphothrips orchidii Moulton, and Chaetanaphothrips signipennis Bagnall (Thysanoptera: Thripidae), and the fungal pathogens: Botrytis cinerea Persoon (Helotiales: Sclerotiniaceae) and Fusarium spp. Link (Hypocreales: Nectriaceae) was examined during a nine-month greenhouse trial in Hawaii. The trial assessed yield, quality, and pest damage across three common varieties of dendrobiums. All replicates received additional soluble silicon fertilizer applications alternating weekly between soil drench and foliar (50 mg Si/plant) applications. Yield, quality, and spray length, pest damage, plant vigor, SPAD, and leaf temperature were measured. Data were analyzed using a generalized linear model (glm) with repeated measures followed by post-hoc pair-wise comparisons in R, version 4.3.1. Treatment effects were significant at p < 0.001 for the majority of the explanatory variables including: marketable yield, spray length, thrips damage, and fungal damage. Overall, the lavender variety ('Uniwai Supreme') benefited the most from silicon applications with a 73.0% increase in marketable yield, compared to the white variety ('Uniwai Mist'), which had an increase of 50.6% marketable sprays in contrast to its untreated control. Si benefits conferred to the purple variety ('Uniwai Royale') were intermediate to the lavender and white varieties. Although the magnitude of Si benefits varied among the varieties, all dendrobium varieties significantly benefited from silicon fertilization.

Building a research model for the combustion process of fuel in a constant volume combustion chamber

ABSTRACT Blending biodiesel at different ratios leads to fluctuations in properties such as oxygen content, cetane number, speed, density, and calorific value, affecting performance and emissions. Therefore, studying the combustion process of biodiesel is necessary. This study describes the construction of a CVCC (Constant volume combustion chamber) model to study the fuel combustion process and the impact of temperature on the characteristic parameters of the combustion process. Fuels used for simulations included diesel fuel and B10 biodiesel derived from palm oil. The calculated results from the model are compared with experimental data to verify, analyse, and evaluate the combustion process in CVCC. Analysis of the influence of combustion chamber temperature shows that increasing the temperature from 300K to 450K leads to a decrease in the mixing time of the mixture, a decrease in the spray length, an increase in the fuel evaporation rate, and the combustion process occurs. Faster, the peak pressure appears earlier and higher, and the heat transfer rate is faster. Pressure increases faster during the delayed combustion phase. At the same time, increasing the oxygen concentration from 10% to 20% also leads to an increase in pressure rate, reaching an earlier peak, and the combustion process occurs faster.

Experimental and numerical investigation of an innovative complex piston with enhanced free spray length for the heavy-duty engine applications

The combustion and emission formation process in heavy-duty compression ignition engines are strongly influenced by the design of the piston bowl, the cylinder charge motion and the performance of the injection system. This paper proposes an innovative complex piston bowl design approach called as ’flower piston’ to improve the combustion process. It can be manufactured using the conventional machining approaches without use of still expensive additive manufacturing techniques. The flower piston features a scooped cavity with an intention of increasing the free fuel spray penetration. The potential of this innovative flower piston is evaluated using a validated 3D CFD model and compared with the results of single cylinder engine experiments at operating points with minimum fuel consumption. The results of the experimental investigations with the flower piston show an improvement in thermal efficiency in comparison to the conventional piston by up to 0.5%. This is due to a faster initial heat release and increased high pressure cycle work. However, the smoke emissions increased threefold due to fuel entrapment into the flower cavities, leading to formation of fuel-rich pockets. Also, the wall heat losses increased twofold with an increase in NOx raw emissions. With increased spray targeting angle, there was a drastic reduction in smoke emissions and an additional improvement in the thermal efficiency.

Optical measurements of two cylindrical and conical heavy-duty diesel injector nozzels – A comparison of reference diesel, HVO, and RME fuels

In the present work, a constant volume/constant pressure combustion chamber was utilized to measure the major parameters of vapour/liquid phases and combustion of fuel spray introduced by two heavy-duty, large-diameter diesel injectors. A conical nozzle (K factor 4) with a 300 µm outlet diameter and a 1300 µm length and a cylindrical nozzle (K factor 0) with a 300 µm outlet diameter and a 650 µm length display notably distinct impacts on the formation of the mixture, the air entrainment process, and the combustion behaviour. Several parameters, including jet and liquid spray penetration lengths, jet cone angle, and jet projected area are combined to describe spray characteristics in an inert background gas, and ignition incidence, flame lift-off length, and soot appearance time parameters are calculated to explain the combustion trend of the nozzles in a reactive gas background. These observations were conducted using four distinct optical techniques, two of Schlieren and Mie-Scattering for inert condition, and two of OH* Chemiluminescence and Natural Flame Luminosity for reactive condition. This study collects a wide variety of boundary conditions, comprising ambient pressure/temperature and fuel rail pressure, with diverse fuels, including reference diesel, HVO, and RME fuels.The findings are categorized by the jet and liquid spray behaviours in the first part, demonstrating that the jet cone angle is an injector geometry-based parameter and that the cylindrical nozzle has a larger cone angle and a shorter liquid spray length. Three distinct scenarios of the computed air-to-fuel mass ratio at the same axial positions, time steps, and injected fuel mass indicate a marginally higher air entrainment in the cylindrical nozzle and, presumably, a faster and better mixture formation. The thorough examination of the combustion characteristics indicates that a quicker formation of the initial stoichiometric region in the cylindrical nozzle results in a shorter ignition delay at most experimental locations, which ultimately results in a faster soot initiation. However, depending on the flame lift-off length and the boundary conditions, the interval between ignition and the development of soot varies considerably. Finally, it is demonstrated that, with the exception of fuel pressure variation, the flame lift-off length, which is crucial in providing the initial mixture formation prior to combustion occurrence, follows the ignition delay trend and exhibits a shorter length with a shorter ignition delay.

Investigating the effects of split injection with different injection patterns on diesel spray mixing

In recent studies, it has been established that improvements in the injection rate results in improved mixing, combustion efficiency, and reduced pollutant emissions. Varying injection rates have been observed to find out the optimization injection rate. In this study, split injection with different injection rates was used as the flexible injection to investigate the diesel spray mixing efficiency. Large eddy simulation (LES) was used to investigate the complex diesel mixing processes of unsteady turbulence. The split injection was combined with different fuel injection rates to approximate the ramping-down rate shape. The simulation results of flexible injection rates showed the formation of a highly unstable aerosol vapor structure with the turbulence structure that produces the vortex in the spray area. The powerful injection rates provide a very strong spray turbulence structure and vortex formation. The backflow and vortex are evident when the dwell time of injection is setup. The flexible injection rates have a huge influence on the mixing efficiency of the fuel spray. Basic mixing efficiency predictions revealed that the dwell time of the split injection and inverse injection pressure affect the turbulence structure. Another prediction is that the initial pressure of the injection rate has a significant impact on evaporation and mixing efficiency, even using the same fuel quantity and same condition. The double-rectangular split injection has a slight effect on the spray radial extension, and the spray area grows rapidly while the equivalence ratio is low. The double-drop split injection with a high pressure difference has a great influence on the spray radial extension and spray length. Additionally, the higher injection pressure results in lower equivalence ratios and more efficient mixing.

Effect on flash boiling spray characteristics in the far-field and near-field and nozzle tip wetting with multi-hole LPDI injector

Flash boiling spray, which has a wider spray width and enhanced interactions plume to plume is likely to favor nozzle tip wetting. To understand the effect of flash boiling spray, this study was aimed that the spray characteristics and nozzle tip wetting of n-heptane and Liquefied petroleum gas (LPG) fuel on LPG direct injection (LPDI) system under various fuel temperature. In addition, the novelty of this study is providing a more detailed understand of spray characteristics affected the fuel properties in the far-field and near-field and nozzle tip wetting by comparing n-heptane and summer LPG under flash boiling conditions. The sprays were divided to three conditions (sub-cooled, transitional, flare flash boiling) based on the degree of superheat. Macroscopic spray characteristics such as spray penetration, spray angle, spray area, and spray length to width ratio were studied in the far-field. Near-field visualization was used to analyze the spray width and spray area. In addition, the wet area and wet boundary on the nozzle tip were visualized using a high-speed camera equipped with a Long-distance microscope (LDM). The experimental results showed that the spray plumes expand and developed in the central axis as fuel temperature increased for both fuels, and the spray plumes were significantly widened in the axial and radial direction for both fuels. The wet area and boundary increased under sub-cooling and transitional conditions as a result of nozzle tip wetting with n-heptane, but the wet area and boundary decreased under transitional and flare conditions. Like n-heptane fuel, the wet area of summer LPG decreased under transitional and flare conditions.

Effects of nozzle hole configuration of a multi-hole type gasoline direct injector on spray development under flash boiling conditions

The flash boiling phenomenon is critically affected by not only injection conditions such as fuel temperature, ambient pressure and physical properties of fuel but also the nozzle hole configurations of the injector. In this research, two kinds of injectors, having different nozzle hole configurations (a closed type and a opened type) were used to analyze the influence of flash boiling. Near-field and far-field spray visualization was performed using a high-speed camera based on the Mie-scattering imaging technique. Test parameters were injection pressure, ambient pressure, and fuel temperature. The spray length, spray width, length-to-width ratio, and axial velocity of spray development depending on time were measured using the MATLAB program for quantitative and objective analysis. Finally, the prediction equation for the spray length was derived using the least-squares method based on the experimental results. In the case of the closed type injector, the spray center contained a wide overlapped region because of the strong links between plumes. On the other hand, with the opened type injector, there was a relatively narrow overlapped region between plumes due to weak interaction between plumes. As a result, the closed type injector had a narrow and long spray structure and the opened type injector had a partially long and wide spray structure. According to the prediction equation, the spray develops depending on time more linearly under flash boiling conditions than under non-flash boiling conditions. The influence of flash boiling was smaller in the closed type injector because the closed type injector has less variation of the spray structure with varying injection conditions, ranging from non-flash boiling conditions to non-flash boiling conditions.

Microscopic characteristics of near-nozzle spray at the initial and end stages

It is demonstrated that the fuel deposit has a significant influence on the NOx and particular matter (PM) emissions, especially with the consideration of the more and more strict emission regulations issued by the governments, which results in that the near-nozzle spray has been received the increased attention, recently. In this study, the near-nozzle spray characteristics at the initial and end stages were investigated by a high-resolution camera with a laser as the light source. At the initial stage, microscopic behaviors of the near-nozzle spray were observed at upstream, midstream and downstream, respectively. Moreover, the injection frequency was changed to check the effect on the near-nozzle spray morphology. Next, the micro spray length, width and angle were obtained from the processed images. While, at the end stage, the near-nozzle spray evolutions were observed and characterized at 0.5, 0.3, 0.2 and 0.1 ms before the end of injection (BEOI), the end of injection (EOI), 0.05, 0.1, 0.15 and 0.2 ms after the end of injection (AEOI), respectively. Furthermore, the droplet area, spray area without droplets, droplet number and averaged diameter were calculated. Results show that three structures of the near-nozzle spray at the initial stage can be classified as mushroom, steeple and cylinder shapes. And the injection frequency has an influence on their formations owing to the residual fuel and sucked air AEOI. Moreover, although more droplets can be identified at the end stage with time, it does not indicate the better atomization. On the contrary, these droplets AEOI are responsible for the injector deposit in the real engine.

Analysis of diesel engine injector nozzle spray characteristics fueled with residual fuel oil

Experimental analysis on the spray characteristics of a diesel engine injector nozzle fueled with Residual Fuel Oil (RFO) was carried out in this study. To achieve this, the fuel was characterized to determine its physicochemical properties, and an experimental set up was designed to visualize and capture the spray pattern of the fuel. The images obtained were processed and analysed using Image J software to determine the spray length, spray cone angle, spray area, spray volume, and spray velocity values of the fuel. Experimental results obtained agree with validation models and reveal that spray parameter values of RFO are higher than those of diesel fuel. The values of spray parameters of RFO such as 456mm spray length, 2.85mm Sauter Mean Diameter (SMD) and the low spray cone angle of 12.69°, led to a higher spray volume causing the engine to run on a rich mixture after initial start-up conditions. This would create such challenges as reduction in power and clogging of injector nozzle tip due to an increase in carbon deposits. Regression models generated reveal that these challenges could be eliminated when the spray parameters run on optimal values of 256mm, 6.41cm2, 16.18cm3, 0.96 mm/s and 13.59° for the spray length, spray area, spray volume, spray velocity and the spray angle respectively. These optimal values were obtained when the engine fuel injection time was set to 500μs while running on fuel of viscosity 4.305 mPa.s and temperature of 48 °C.

Influence of Biodiesel Blended in Gasoline-Based Fuels on Macroscopic Spray Structure from a Diesel Injector

This research investigates the spray characteristics of gasoline-biodiesel blended fuels (GB), which expected to be utilized in a gasoline compression ignition engine. Commercial gasoline blended with 0 ∼ 20 % by volume of biodiesel, called GB00 – GB20, were used to experiment. In addition, neat biodiesel and pure gasoline were also investigated as the references. Firstly, the chemical and physical properties of the GB blends were characterized to clarify the effect of biodiesel content. Then, spray macroscopic visualization was performed by the shadowgraph technique. The test fuels at injection pressures of 1,000, 1,200, and 1,350 bar were injected into a constant volume combustion chamber (CVCC). The constant back pressures in the CVCC were set at 30 bar and 50 bar. The spray penetrating length and cone angle were analyzed by an image processing technique. Biodiesel is characterized as the widest angle and longest spray length while gasoline has the narrowest cone angle and shortest penetration. There is no correlation between the spray angle/penetration length and the percentage of biodiesel in the blends among the GB. When the injection pressure was increased, the spray cone angle was slightly decreased, while the spray-penetrating length was increased for all test fuels.

Evaluation of Atomization Characteristics of Second Generation Biodiesel Using Air Blast Atomizer

Biodiesel is one of the well-known renewable fuels that can be produced from organic oils and animal fats. Biodiesel fuel that meets ASTM D6751 fuel standards can replace diesel for reciprocating engine. On the other hand, biodiesel can also be considered for gas turbine application in power generation. Nevertheless, inferior properties of biodiesel such as high viscosity, density and surface tension results in inferior atomization and high emission which consequently hinders the fuel for gas turbine utilisation and generate higher emission pollutants. Therefore, this work focused on the evaluation of atomization characteristics of second generation biodiesel which is produced using microwave assisted post treatment scheme. The atomisation characteristics of second generation biodiesel was evaluated using air blast atomiser in terms of spray angle and spray length. Subsequently, numerical evaluation was performed to evaluate sauter mean diameter and droplet evaporation time of second generation biodiesel. The results show, atomization characteristics of second generation biodiesel has improved in terms of spray angle and spray length, sauter mean diameter and shorter evaporation time compared to biodiesel which is commonly referred to as first generation biodiesel and fossil diesel.

The influence of in-nozzle cavitation on flow characteristics and spray break-up

In the presented paper, a combined experimental and numerical study was carried out in order to study the influence of in-nozzle flow, cavitation and tested fuel properties on the spray development and primary break up process. The internal flow of neat diesel and neat rapeseed oil biodiesel fuel in single-hole diesel injectors was studied numerically using the AVL FIRE computational program. The spray development and break-up were monitored in a pressure chamber at high pressure using a high-speed camera. An innovative method for obtaining spray length and cone angle was developed using LabVIEW software. The developed method allows us to study the influence of in-nozzle cavitation inception on the symmetry of injected fuel spray. The obtained numerical results show that the geometry of the test injector influences internal fuel flow and cavitation inception highly. Experimental results indicate that tested fuel properties‘ influence spray length and cone angle at high atmospheric pressure is rather small. The cavitation inside the injector nozzle influences the primary spray break-up process further and causes part of the spray, where more cavitation is present in the nozzle hole and its exit, to disintegrate. This confirms that cavitation inside the fuel injector can have a positive effect on the spray break-up and spray disintegration process.

Modelling of liquid nitrogen spray cooling in an electronic equipment cabin under low pressure

Timely and effective cooling is essential for the performance of electronic equipment. For spacecraft, however, the severe aerodynamic heating and low-pressure environment have posed a serious challenge to the heat removal of the high-power electronic equipment. Spray cooling is considered to be an appropriate way to maintain the temperature of the electronic devices within acceptable limits. This paper considers the heat balance in spray cooling using a First Law of Thermodynamics modelling approach as well as a thermal control strategy for a semi-enclosed electronic equipment cabin. Theoretical analysis and numerical results are presented to show the applicability of the developed model and strategy. Characteristics of liquid nitrogen droplet heating, boiling and flash evaporation as well as spray patterns are discussed in detail. Furthermore, the control method of the spray nozzles switching and the interaction mechanism between pressure and temperature within the electronic equipment cabin during spray cooling are also addressed. The thermal control strategy and the model predictions presented in this work can help researchers and designers to ascertain optimum operational conditions of spraying cooling, including the spray mass flow rate, the spray length and the distribution of the sprayed droplets.

고밀도 균일 안개스크린을 위한 에어로졸 유동의 최적 생성조건

The fog screen is a device projecting the media to the aerosol flow field. As major parameters to generate dense and steady fog screen, shear stress, optical blockage ratio and SMD were obtained result through experiment. The micro droplet was generated by the piezo oscillation element, and the aerosol flow mixed with an air flow was sprayed into the vertical direction from the top of the fog screen through the 280 mm slot. For produce a dense, uniform fog screen, the shear effect, optical blockage ratio and SMD between aerosol and air curtain were measured. The minimum and maximum shear stress conditions were selected and it was confirmed that the optical transmission deviation of the aerosol flow field was small when the aerosol and air curtain flow rates were changed. When the aerosol and air curtain flow power were 18 V (1.51 m/s) and 24 V (2.55 m/s), respectively, under the condition of the minimum shear stress and laminar flow, the optical blockage ratios with the spray length were small, and it produced a most stable and high density uniform fog screen by injecting a constant of <TEX>$10{\mu}m$</TEX> or less.

Air assist atomization characterization of palm biodiesel through experimental investigation and CFD simulation

ABSTRACTThe depletion of fossil fuel and environmental concerns have elevated biodiesel to emerge as a suitable alternative fuel to substitute diesel fuel. The study of spray formation is essential to improve the combustion systems of internal combustion engines and gas turbines. This paper aims to study the atomization characteristics of biodiesel derived from palm biodiesel through experimental test and simulation. The chemical fuel properties of biodiesel such as viscosity and density, will adversely affect the spray characteristics such as spray pattern, spray length, spray angle and Sauter Mean Diameter. The biodiesel fuels are blended with diesel in various ratios before being tested in an atomization test rig. Modelling of the atomizer are presented using computational fluid dynamics whereby comparisons are made with respect to the experimental results carried out in the atomizer test rig. There is no large discrepancy with the simulation results. The results showed that the higher content of biodiesel gives a larger droplet size and longer spray length. However, it produces smaller spray angle and spray width but with clearer vortex shape of spray pattern.

Spray and atomization of a common rail fuel injector with non-circular orifices

Abstract This paper presents an experimental study on diesel sprays from non-circular orifices in ambient air. The non-circular geometry includes rectangular, square, and triangular shapes. The obtained spray characteristics were compared with those of a circular orifice. The injection pressures were varied from 300 bar (30 MPa) to 1000 bar (100 MPa). Macroscopic spray characteristics like spray cone angle and spray width were measured using a high speed camera. A laser diffraction technique was used to measure the droplet size, i.e. Sauter mean diameter, of the sprays at different axial locations. Spray behavior was measured from different orientations of the non-circular geometric shapes, including edges and corners. Spray widths measured along the spray length clearly demonstrated the presence of axis-switching phenomenon in high pressure diesel sprays obtained from non-circular orifices even at injection pressures as high as 1000 bar. They also exhibited larger widths and hence, larger surface areas, greater cone angles than sprays from a circular orifice. Thus, sprays from non-circular geometric shapes are expected to achieve better air entrainment and hence, mixing than the circular orifices. Droplet size obtained depended on the location of measurement and injection pressure and different behaviors were observed at different locations. It was noticed that non-circular orifices could induce greater instabilities in the diesel sprays thereby leading to faster atomization. As a result, an improvement in the spray characteristics can be achieved using non-circular geometries. Axis-switching phenomenon is expected to play an important role in improving the spray characteristics and the non-circular geometry may provide a cost effective approach for passively controlling the spray characteristics.

Studies on genetic variability and character association for yield and its attributes in chrysanthemum (Dendranthema grandifloraTzvelev)

One hundred and four divergent genotypes of chrysanthemum were evaluated to study their genetic variability, correlations and path coefficients during 2011-12. Higher estimates for GCV and PCV were observed for all the characters studied except for plant height, days to flowering, spray length and duration of flowering showing ample scope for selection of those characters. High heritability coupled with high genetic advance as percentage of mean was recorded for all the quantitative characters studied except for duration of flowering. A significant positive correlation both at genotypic and phenotypic levels was recorded between flower yield and plant attributes viz., plant spread at both the directions, number of primary branches per plant, spray length and number of flowers per spray. Path coefficient analysis revealed that plant spread in N-S direction recorded the highest direct effect on flower yield per plant followed by number of flowers per spray, days to 50% flowering, number of primary branches per plant, average flower weight and duration of flowering. Hence the direct selection from germplasm lines for these characters may be effective for further improvement of the crop.

A study on the 0D phenomenological model for diesel engine simulation: Application to combustion of Neem methyl esther biodiesel

The design and monitoring of modern diesel engines running on alternative fuels require reliable models that can validly substitute experimental tests and predict their operating characteristics under different load conditions. Although there exists a multitude of models for diesel engines, 0D phenomenological models present the advantages of giving fast and accurate computed results. These models are useful for predicting fuel spray characteristics and instantaneous gas state. However, there are few reported studies on the application of 0D phenomenological models on biodiesel fuel combustion in diesel engines.This work reports the elaboration, validation and application on Neem methyl ester biodiesel (NMEB) combustion of a 0D phenomenological model for diesel engine simulation.The model addresses some specific aspects of diesel engine modeling found in previous studies such as the compromise between computers cost, accurateness and model simplicity, the reduction of the number of empirical fitting constant, the prediction of combustion kinetics with reduction of the need of experimental curve fitting, the ability to simultaneously predict under various loads engine thermodynamic and spray parameters as well as emission characteristics and finally the ability to simulate diesel engine parameters when fueled by alternative fuels.The proposed model predicts fuel spray behavior, in cylinder combustion and nitric oxides (NOx) emissions. The model is implemented through a Matlab code. The model is mainly based on Razlejtsev’s spray evaporation model, Watson’s double Wiebe function and Ferguson’s tabulated chemistry thermodynamic cycle algorithm. NOx emissions are implemented in the model using the extended Zeldovich mechanism, heat transfer and ignition delay are also taken into account in the model.Following the validation in different operating points of the model on a four stroke 1 – cylinder direct injection diesel engine, the operating characteristics were predicted with an average error accuracy of about 15%. The relative error is, respectively, 10% for Sauter diameter, 12% for maximum penetration, 9.8% for peak pressure, 7.38% for peak temperature, 10.7% for NOx emission and 13.7% for engine power output. The model predicts higher Sauter mean diameter, higher fuel spray length and NOx emission for NMEB as compared to conventional diesel fuel which is in accordance with experimental results obtained on biodiesel fuels in previous researches. Methyl butyrate and methyl butanoate thermochemical data were used as surrogates for NMEB, the results obtained from the model were close, independently of the surrogate used for biodiesel. The average simulation time for a full cycle simulation was about 94.22s, which gives to the model applicability for diesel engine optimization purposes. The results obtained were found satisfactory in terms of accuracy, algorithm simplicity and computer cost.

An Analysis of the Ambient Condition Effect on Biodiesel Spray Using Constant Volume Chamber

Diesel engines are high compression ignition engine which are now very vastly used for heavy vehicles and machineries. Diesel fuel is compressed under the right condition to ignite inside the constant volume chamber. Researchers have been studying for many years on ways to increase the efficiency of diesel engine as well as reduce the emission. The main idea of this research is to understand the effect of temperature on the spray characteristics, as well as fuel-air mixing characteristics. These are the characteristics responsible for ignition of diesel sprays. This research is first conducted by investigating the influence of biodiesel properties and ambient condition on the mixture formation especially at early stage of fuel-air premixing. This research was continued with injecting diesel fuel into the chamber using a Bosch common rail system. Direct photography technique with a digital camera was used to capture the real images of spray evaporation, spray length, and mixture formation with the time changes. The values of the temperature were recorded at ambient temperature, 55°C, 70°C, 85°C as well as 100°C. Injection pressure of 0.1 MPa up to 0.7 MPa was induced into the chamber with an increment of 0.1 MPa. The condition to which the fuel is affected was estimated by combining information on the block temperature, ambient temperature and photographs of the spray. The increase in block temperature increases the ambient temperature inside the chamber resulting in gain of spray area and wider spray angle. Thus predominantly promotes for a better fuel-air mixing.