# Numerical Analysis of Nozzle Flow and Spray Characteristics from Different Nozzles Using Diesel and Biofuel Blends

^{1}

^{2}

^{3}

^{*}

*Energies*

**2019**,

*12*(2), 281; https://doi.org/10.3390/en12020281 (registering DOI)

## Abstract

**:**

## 1. Introduction

_{x}was identified to be smaller compared to the diesel.

## 2. Mathematical Model

#### 2.1. Injector Flow Phase

_{i}is the fluid velocity, $\dot{\gamma}$ is the shear stress, and g

_{i}= −9.81 m/s is the gravitational acceleration at the earth’s surface.

#### 2.2. Discrete Particle Phase

_{p}is the fluid density; u is the velocity of the particle and u

_{p}is the velocity of the fluid phase; F

_{x}is the other forces that interact with the particles due to mass, acceleration, and pressure; and F

_{D}(u − u

_{p}) is the drag force that equates to each of the particles, where F

_{D}is defined as:

_{p}is the particle density, C

_{D}is the particles drag coefficient, Re is the Reynolds number, and d

_{p}is the particle diameter of the droplets that are assumed as spheres in this study. The equation for C

_{D}is given as:

_{1}, α

_{2}, and α

_{3}are constants based on the ranges of Reynolds number.

_{other}is the additional interaction forces, Δt is the time step, and ṁ

_{p}is the particle mass flow rates. The particle trajectory can be calculated using:

_{T}is the thermophoric coefficient, which use the form suggested by Talbot [33]:

_{c}is the fluid thermal conductivity based on translational energy only, k

_{p}is the particle thermal conductivity, m

_{p}is the particle mass, µ is the fluid viscosity, C

_{s}= 1.17, C

_{t}= 2.18, and C

_{m}= 1.14.

#### 2.3. Spray Simulations

#### 2.3.1. Primary Breakup Modeling

_{KH}) and corresponding wavelength (Λ

_{KH}) according to Reitz [36] is calculated using:

_{g}denoting the gas density, ρ

_{l}is the liquid density, σ is surface tension, U

_{r}is the magnitude of velocity between two phases, and v

_{l}is the liquid viscosity.

_{KH}occurred due to a decrease in the droplet radius. Hence, the breakup time τ

_{KH}and the critical droplet radius r

_{KH}are calculated by:

_{0}= 0.61 and B

_{l}= 20.

_{RT}) is given by:

_{t}is the droplet acceleration. The wave number is computed using:

_{T}waves were propagating, the time becoming larger than the breakup time τ

_{RT}breakup will occur. The τ

_{RT}is calculated using:

_{τ}is the Rayleigh–Taylor breakup time constant. Then, the radius of the smaller droplets is given using:

_{RT}is the breakup radius constant.

#### 2.3.2. Secondary Breakup Modeling

_{0}is the initial flow velocity, l

_{0}is the characteristic diameter of the obstacle, and t

_{0}is the particle relaxation time.

## 3. Experimental Procedures

#### 3.1. Fuel Preparation

#### 3.2. Fuel Properties

#### 3.3. Experiment Setup

## 4. Simulation Methodology

^{−3}to 10

^{−4}. The range of time step was set between 1.0 × 10

^{−6}s to 1.0 × 10

^{−8}s. The fuels used for this study are listed in Table 1.

#### Grid Independence Tests

## 5. Result and Discussion

#### 5.1. Model Validation

_{s}is the widths of the spray cloud, which were denoted as a length between the spray cloud borders.

#### 5.2. Nozzle Flow Simulations

#### 5.3. Spray Simulation Results

#### 5.3.1. Spray Images Growth

#### 5.3.2. Spray Tip Penetration

#### 5.3.3. Spray Cone Angle

#### 5.3.4. Spray Width

_{S}) over the nozzle hydraulic diameters (D) has been used to compare the data of spray width. The spray widths were taken into account to compare the spray characteristics of different nozzle shapes under the real diesel engine and high-pressure conditions. Figure 17 displays the results of spray width (W

_{S}/D) along the spray axis length. As can be seen from Figure 17, the spray width of the elliptical A and elliptical B nozzle shapes was much larger than that of the circle shape for all pressure conditions. Furthermore, the spray width of elliptical B was much bigger than the elliptical A nozzle shape. These results showed that the superior spray atomization and bigger spray cone angle could be achieved by using elliptical A and elliptical B nozzle shape compared to a circular nozzle shape. From the graph in Figure 17, it is apparent that the elliptical A and B spray widths were fluctuating along the spray axis length. This investigation shows that elliptical A and elliptical B experienced an axis-switching phenomenon under the real diesel engine and high-pressure conditions. What is interesting in this data is that as the backpressure was increased with the same injection pressure, the axis-switching phenomenon of the spray width decreased. The current study found that the aerodynamic effects could be boosted by increasing the backpressure. Another important finding was that the high-pressure conditions were useful to reduce the axis-switching phenomenon. All the nozzle shapes demonstrated higher spray width when the injection pressure was increased. It seems possible that these results were due to a higher difference between inlet and outlet velocity and steady air and fuel interaction were achieved when the spray velocity became greater under a higher injection pressure. These findings of the current study were consistent with those of Abramovich [44] who found that axis-switching was due to pressure differentials in the plane of the vortex ring.

## 6. Conclusions

- The nozzle flow simulation results indicated that the fuel type had little effect on the cavitation area and it is dependence on the nozzle spray shape. The diesel delivered slightly a higher average velocity than hybrid biofuel under high injection pressure (180 MPa). These behaviors were generally caused by viscosity and density properties. The cavitations intensity was more intensive for elliptical A and elliptical B as compared to the circle nozzle shape for the same injection time. The aspect ratio of the elliptical nozzle shape was found to affect the cavitations flow, where the elliptical B cavitations intensity was more intensive than the elliptical A nozzle shape.
- The droplet size of the elliptical nozzle shape was smaller compared to the circular shape due to higher aerodynamic effects found in the elliptical nozzle shape that could reduce the droplets size, and thus leading to a bigger cloud formation after the secondary breakup. The evidence from this study suggests that the droplet size became smaller when the pressure was increased for both diesel and hybrid biofuel
- The spray tip penetration of the elliptical nozzle shape was smaller than the circular nozzle shape. This was due to the circular nozzle having smaller spray widths and cone angles. Further analysis showed that the type of fuel on the different nozzle shape had a small effect towards the spray tip penetration, although diesel fuel gave a slightly higher spray tip penetration compared to hybrid biofuel blends. In addition, the spray tip penetration was affected by the aspect ratio of the elliptical nozzle shape.
- The elliptical nozzle shape was larger compared to the circular nozzle shape in terms of spray cone angles. The spray cone angle for elliptical B was found to be much higher than that of elliptical A. This indicated that the aspect ratio of the elliptical nozzle shape was found to affect the spray cone angles. Moreover, the type of fuel on the different nozzle shape had a minor influence to the spray cone angles. The results show that diesel produced smaller cone angles compared to the biofuel blend.
- The spray widths of the circular nozzle shape were smaller than those of the elliptical A and elliptical B under all injection pressures and backpressures. However, the fuel type had little effect on the spray widths for all the nozzle shape. Furthermore, the aspect ratio of the elliptical nozzle shape was found to affect the spray width.

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

## References

- Shervani-Tabar, M.T.; Sheykhvazayefi, M.; Ghorbani, M. Numerical study on the effect of the injection pressure on spray penetration length. Appl. Math. Model.
**2013**, 37, 7778–7788. [Google Scholar] [CrossRef] - Sidibé, S.S.; Blin, J.; Vaitilingom, G.; Azoumah, Y. Use of crude filtered vegetable oil as a fuel in diesel engines state of the art: Literature review. Renew. Sustain. Energy Rev.
**2010**, 14, 2748–2759. [Google Scholar] [CrossRef] - Qian, D.; Liao, R. A Nonisothermal Fluid-Structure Interaction Analysis on the Piston/Cylinder Interface Leakage of High-Pressure Fuel Pump. J. Tribol.
**2014**, 136, 21704–21708. [Google Scholar] [CrossRef] - Hussain, F.; Husain, H.S. Elliptic jets. Part 1. Characteristics of unexcited and excited jets. J. Fluid Mech.
**1989**, 208, 257–320. [Google Scholar] [CrossRef] - Ge, C.J.; Yoon, K.S.; Choi, J.N. Using Canola Oil Biodiesel as an Alternative Fuel in Diesel Engines: A Review. Appl. Sci.
**2017**, 7, 881. [Google Scholar] [CrossRef] - Suresh, M.; Jawahar, C.P.; Richard, A. A review on biodiesel production, combustion, performance, and emission characteristics of non-edible oils in variable compression ratio diesel engine using biodiesel and its blends. Renew. Sustain. Energy Rev.
**2018**, 92, 38–49. [Google Scholar] [CrossRef] - Shi, S.; Valle-Rodríguez, J.O.; Siewers, V.; Nielsen, J. Prospects for microbial biodiesel production. Biotechnol. J.
**2011**, 6, 277–285. [Google Scholar] [CrossRef] [PubMed] [Green Version] - Rahman, Z.; Nawab, J.; Sung, H.B.; Kim, C.S. A Critical Analysis of Bio-Hydrocarbon Production in Bacteria: Current Challenges and Future Directions. Energies
**2018**, 11, 2663. [Google Scholar] [CrossRef] - Yellapu, S.K.; Bharti; Kaur, R.; Kumar, L.R.; Tiwari, B.; Zhang, X.; Tyagi, R.D. Recent developments of downstream processing for microbial lipids and conversion to biodiesel. Bioresour. Technol.
**2018**, 256, 515–528. [Google Scholar] [CrossRef] [PubMed] - Zhang, M.; Wu, H. Effect of major impurities in crude glycerol on solubility and properties of glycerol/methanol/bio-oil blends. Fuel
**2015**, 159, 118–127. [Google Scholar] [CrossRef] - Meher, L.C.; Vidya Sagar, D.; Naik, S.N. Technical aspects of biodiesel production by transesterification—A review. Renew. Sustain. Energy Rev.
**2006**, 10, 248–268. [Google Scholar] [CrossRef] - Rakopoulos, C.D.; Antonopoulos, K.A.; Rakopoulos, D.C.; Hountalas, D.T.; Giakoumis, E.G. Comparative performance and emissions study of a direct injection Diesel engine using blends of Diesel fuel with vegetable oils or bio-diesels of various origins. Energy Convers. Manag.
**2006**, 47, 3272–3287. [Google Scholar] [CrossRef] - Channapattana, S.V.; Kantharaj, C.; Shinde, V.S.; Pawar, A.A.; Kamble, P.G. Emissions and Performance Evaluation of DI CI—VCR Engine Fuelled with Honne oil Methyl Ester/Diesel Blends. Energy Procedia
**2015**, 74, 281–288. [Google Scholar] [CrossRef] - Desantes, J.M.; Payri, R.; Salvador, F.J.; Manin, J. Influence on Diesel Injection Characteristics and Behavior Using Biodiesel Fuels; SAE International: Warrendale, PA, USA, 2009. [Google Scholar]
- Priesching, P.; Pavlovic, Z.; Ertl, P.; Del Giacomo, N.; Beatrice, C.; Mancaruso, E.; Vaglieco, B.M. Numerical and Experimental Investigation of the Influence of Bio-Diesel Blends on the Mixture Formation, Combustion and Emission Behavior of a Modern HSDI Diesel Engine; SAE International: Warrendale, PA, USA, 2009. [Google Scholar]
- Allocca, L.; Mancaruso, E.; Montanaro, A.; Vaglieco, B.M.; Vassallo, A. Renewable Biodiesel/Reference Diesel Fuel Mixtures Distribution in Non-Evaporating and Evaporating Conditions for Diesel Engines; SAE International: Warrendale, PA, USA, 2009. [Google Scholar]
- Sem, T.R. Investigation of Injector Tip Deposits on Transport Refrigeration Units Running on Biodiesel Fuel; SAE International: Warrendale, PA, USA, 2004. [Google Scholar]
- Ramadhas, A.S.; Jayaraj, S.; Muraleedharan, C. Characterization and effect of using rubber seed oil as fuel in the compression ignition engines. Renew. Energy
**2005**, 30, 795–803. [Google Scholar] [CrossRef] - Mohan, B.; Yang, W.; Yu, W.; Tay, K.L.; Chou, S.K. Numerical Simulation on Spray Characteristics of Ether Fuels. Energy Procedia
**2015**, 75, 919–924. [Google Scholar] [CrossRef] [Green Version] - Lee, Y.; Huh, K.Y. Numerical study on spray and combustion characteristics of diesel and soy-based biodiesel in a CI engine. Fuel
**2013**, 113, 537–545. [Google Scholar] [CrossRef] - Som, S.; Ramirez, A.I.; Longman, D.E.; Aggarwal, S.K. Effect of nozzle orifice geometry on spray, combustion, and emission characteristics under diesel engine conditions. Fuel
**2011**, 90, 1267–1276. [Google Scholar] [CrossRef] - Mohan, B.; Yang, W.; Yu, W.; Tay, K.L. Numerical analysis of spray characteristics of dimethyl ether and diethyl ether fuel. Appl. Energy
**2017**, 185, 1403–1410. [Google Scholar] [CrossRef] - Zhou, Z.-F.; Lu, G.-Y.; Chen, B. Numerical study on the spray and thermal characteristics of R404A flashing spray using OpenFOAM. Int. J. Heat Mass Transf.
**2018**, 117, 1312–1321. [Google Scholar] [CrossRef] - Kegl, B.; Lešnik, L. Modeling of macroscopic mineral diesel and biodiesel spray characteristics. Fuel
**2018**, 222, 810–820. [Google Scholar] [CrossRef] - Pairan, M.R.; Asmuin, N.; Isa, N.M.; Sies, F. Characteristic study of flat spray nozzle by using particle image velocimetry (PIV) and ANSYS simulation method. AIP Conf. Proc.
**2017**, 1831, 20009. [Google Scholar] [CrossRef] - Kuleshov, A.S. Use of Multi-Zone DI Diesel Spray Combustion Model for Simulation and Optimization of Performance and Emissions of Engines with Multiple Injection; SAE Technical Paper; SAE International: Warrendale, PA, USA, 2006; Volume 1385. [Google Scholar]
- Battistoni, M.; Grimaldi, C.N. Numerical analysis of injector flow and spray characteristics from diesel injectors using fossil and biodiesel fuels. Appl. Energy
**2012**, 97, 656–666. [Google Scholar] [CrossRef] - Lin, S.; Ding, L.; Zhou, Z.; Yu, G. Discrete model for simulation of char particle gasification with structure evolution. Fuel
**2016**, 186, 656–664. [Google Scholar] [CrossRef] - Rashidi, S.; Bovand, M.; Abolfazli Esfahani, J.; Ahmadi, G. Discrete particle model for convective AL
_{2}O_{3}–water nanofluid around a triangular obstacle. Appl. Therm. Eng.**2016**, 100, 39–54. [Google Scholar] [CrossRef] - Thiruvengadam, M.; Zheng, Y.; Tien, J.C. DPM simulation in an underground entry: Comparison between particle and species models. Int. J. Min. Sci. Technol.
**2016**, 26, 487–494. [Google Scholar] [CrossRef] - Di Sarli, V.; Russo, P.; Sanchirico, R.; Di Benedetto, A. CFD simulations of the effect of dust diameter on the dispersion in the 20L bomb. Chem. Eng. Trans.
**2013**, 31, 727–732. [Google Scholar] - Song, X.; Park, Y.C. Numerical Analysis of Butterfly Valve-Prediction of Flow Coefficient and Hydrodynamic Torque Coefficient. In Proceedings of the World Congress on Engineering and Computer Science, San Francisco, CA, USA, 24–26 October 2007; pp. 2–6, ISBN 978-988-98671-6-4. [Google Scholar]
- Talbot, L.; Cheng, R.K.; Schefer, R.W.; Willis, D.R. Thermophoresis of particles in a heated boundary layer. J. Fluid Mech.
**1980**, 101, 737–758. [Google Scholar] [CrossRef] - Turner, M.R.; Sazhin, S.S.; Healey, J.J.; Crua, C.; Martynov, S.B. A breakup model for transient Diesel fuel sprays. Fuel
**2012**, 97, 288–305. [Google Scholar] [CrossRef] [Green Version] - Reitz, R.D.; Beale, J.C. Modeling Spray Atomization with The Kelvin-Helmholtzrayleigh-Taylor Hybrid Model. At. Sprays
**1996**, 9, 623–650. [Google Scholar] [CrossRef] - Reitz, R. Modeling atomization processes in high-pressure vaporizing sprays. At. Spray Technol.
**1987**, 3, 309–337. [Google Scholar] - Taylor, G.I. The shape and acceleration of a drop in a high speed air stream. Sci. Pap. G I Taylor
**1963**, 3, 457–464. [Google Scholar] - O’Rourke, P.J.; Amsden, A.A. The Tab Method for Numerical Calculation of Spray Droplet Breakup; SAE International: Warrendale, PA, USA, 1987. [Google Scholar]
- Lee, S.-J.; Baek, S.-J. The effect of aspect ratio on the near-field turbulent structure of elliptic jets. Flow Meas. Instrum.
**1994**, 5, 170–180. [Google Scholar] [CrossRef] - Salvador, F.J.; Gimeno, J.; Pastor, J.M.; Martí-Aldaraví, P. Effect of turbulence model and inlet boundary condition on the Diesel spray behavior simulated by an Eulerian Spray Atomization (ESA) model. Int. J. Multiph. Flow
**2014**, 65, 108–116. [Google Scholar] [CrossRef] [Green Version] - Yu, S.; Yin, B.; Deng, W.; Jia, H.; Ye, Z.; Xu, B.; Xu, H. Experimental study on the spray characteristics discharging from elliptical diesel nozzle at typical diesel engine conditions. Fuel
**2018**, 221, 28–34. [Google Scholar] [CrossRef] - Pastor, J.V.; Arrègle, J.; Palomares, A. Diesel spray image segmentation with a likelihood ratio test. Appl. Opt.
**2001**, 40, 2876–2885. [Google Scholar] [CrossRef] [PubMed] - Chen, N.; Yu, H. Mechanism of axis switching in low aspect-ratio rectangular jets. Comput. Math. Appl.
**2014**, 67, 437–444. [Google Scholar] [CrossRef] - Abramovich, G.N. On the deformation of the rectangular turbulent jet cross-section. Int. J. Heat Mass Transf.
**1982**, 25, 1885–1894. [Google Scholar] [CrossRef]

**Figure 4.**TAB model analogy [38].

**Figure 10.**Spray tip penetration growth for a circular nozzle shape with 50 MPa of pressure and 3 MPa of backpressure for the experiments and simulation.

**Figure 11.**Evolution of spray cone angle for a circular nozzle shape with 50 MPa of pressure and 3 MPa of backpressure for experiments and simulation.

**Figure 12.**Cavitation in diesel nozzle for different nozzle spray shape with an injection pressure of 180 MPa.

**Figure 13.**Outlet Average liquid velocity under 180 MPa pressure for different type of nozzle shape and fuel.

**Figure 14.**Fuel spray images at 0.9 ms ASOI for elliptical and circular nozzle types: (

**a**) 50 MPa pressure injection, (

**b**) 100 MPa pressure injection, and (

**c**) 180 MPa pressure injection.

**Figure 15.**Spray tip penetration under different pressures: (

**a**) 50 MPa pressure injection, (

**b**) 100 MPa pressure injection, and (

**c**) 180 MPa pressure injection.

**Figure 16.**Spray cone angle for different types of nozzle shape and fuel: (

**a**) 50 MPa pressure injection, (

**b**) 100 MPa pressure injection, and (

**c**) 180 MPa pressure injection.

**Figure 17.**Ratio of spray width over nozzle hydraulic diameters (

**a**) 50 MPa pressure injection; (

**b**) 100 MPa pressure injection; (

**c**) 180 MPa pressure injection.

Types of Fuel | Density (kg/m^{3}) | Surface Tension (N/m) | Dynamic Viscosity (mPas) | Kinematic Viscosity (mm^{2}/s) (40 °C) | Vapor Pressure |
---|---|---|---|---|---|

Diesel | 830 | 0.0273 | 2.7 | 2.57 | 0.1 kPa at 40 °C |

RP032MC068 (hybrid biofuel) | 882 | 0.032 | 5.2 | 5.9 | 1 hPa at 133 °C |

Nozzle Type | Circle | Elliptical A | Elliptical B |
---|---|---|---|

Major Axis (M) (mm) | 0.160 | 0.170 | 0.189 |

Minor Axis (m) (mm) | 0.160 | 0.142 | 0.135 |

Aspect ratio (M/m) | 1 | 1.2 | 1.4 |

Area (mm^{2}) | 0.02 | 0.019 | 0.02 |

Orifice length (mm) | 1.23 | 1.23 | 1.23 |

Engine Type | 2.2-L Turbocharged DI Diesel Engine | In-line, Turbocharged, Intercooled |
---|---|---|

Cylinder number-Bore × Stroke (mm) | 4-86 × 94.6 | 6-110 × 115 |

Rated Power/Speed (kW/r/min) | 155/3800 | 155/2300 |

Maximum Torque/Speed (N·m/r/min) | 360/1500 | 680/1400 |

Minimum brake specific fuel consumption BSFC (g/kW·h) | 222 | 205 |

The nozzle hole diameter of injectors (mm) | 0.12 | 0.17 |

Boundary | Boundary Conditions |
---|---|

Injection pressure | 50 MPa, 100 MPa, 180 MPa |

Backpressure | 1 MPa, 3 MPa |

Ambient air temperature | T = 300 K |

After start of injection (ASOI) | 0–1 ms |

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

Ishak, M.H.H.; Ismail, F.; Che Mat, S.; Abdullah, M.Z.; Abdul Aziz, M.S.; Idroas, M.Y.
Numerical Analysis of Nozzle Flow and Spray Characteristics from Different Nozzles Using Diesel and Biofuel Blends. *Energies* **2019**, *12*, 281.
https://doi.org/10.3390/en12020281

**AMA Style**

Ishak MHH, Ismail F, Che Mat S, Abdullah MZ, Abdul Aziz MS, Idroas MY.
Numerical Analysis of Nozzle Flow and Spray Characteristics from Different Nozzles Using Diesel and Biofuel Blends. *Energies*. 2019; 12(2):281.
https://doi.org/10.3390/en12020281

**Chicago/Turabian Style**

Ishak, M.H.H., Farzad Ismail, Sharzali Che Mat, M.Z. Abdullah, M.S. Abdul Aziz, and M.Y. Idroas.
2019. "Numerical Analysis of Nozzle Flow and Spray Characteristics from Different Nozzles Using Diesel and Biofuel Blends" *Energies* 12, no. 2: 281.
https://doi.org/10.3390/en12020281