Contact angle measurements for automotive exterior water management

Hodgson, Graham; Passmore, Martin A.; Skarysz, Maciej; Garmory, Andrew; Paolillo, Franck

doi:10.1007/s00348-021-03219-2

Cited by 10 publications

(4 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…No atomisation is included in this simulation as the outlets are placed parallel with the prefilmer trailing edge. A fixed contact angle of 8.65°is applied to the prefilmer surface, based on the work of Hodgson et al [20] and Ray [21].…”

Section: Film Development Simulationmentioning

confidence: 99%

The Effect of Film Development on Primary Breakup in a Prefilming Airblast Atomizer

Wetherell,

Garmory

2024

Journal of Engineering for Gas Turbines and Power

View full text Add to dashboard Cite

Liquid fuelled gas turbines are likely to remain a dominant force in aviation propulsion for the foreseeable future, and therefore understanding the atomisation process is key to meeting future emissions and performance legislation. To make experiments and simulations possible, simplified geometry and boundary conditions are often used, for example, simulations of primary atomisation often use a fixed film height and velocity. This paper aims to quantify the effect of a fully developed unsteady film on the atomisation process. A custom Coupled Level Set & Volume of Fluid (CLSVOF) solver with adaptive meshing built in OpenFOAM v9 is used. A simulation of the atomisation process in the Karlsruhe Institute of Technology atomisation experiment (Warncke et al., 2017) is presented. A precursor simulation of the film development is used to provide accurate, temporally and spatially resolved inlet boundary conditions. These results are compared to previous CLSVOF simulations from Wetherell et al. (2020) using traditional boundary conditions. The unsteady film has doubled the modal ligament length and widened the distribution, and is now in better agreement with experimental measurements. A clear correlation in both time and space is observed between the film, atomisation process, and spray. The SMD is significantly increased, again giving better agreement with the experiment. A discussion of extracting statistical descriptions of the spray is given, outlining the unfeasible computational cost required to converge droplet diameter distributions and other high order statistics for a case such as this.

show abstract

Section: Film Development Simulationmentioning

confidence: 99%

The Effect of Film Development on Primary Breakup in a Prefilming Airblast Atomizer

Wetherell,

Garmory

2024

Journal of Engineering for Gas Turbines and Power

View full text Add to dashboard Cite

show abstract

“…Hodgson et al [38] have recently developed a new method for the measurement of contact angles, both static and dynamic. Using this method the static contact angle of kerosene on stainless steel was measured as 9°and a new simulation run with this contact angle, the results of which are shown in Fig.…”

Section: Impact Of Contact Anglementioning

confidence: 99%

Air-film coupling in prefilming airblast atomisers and the implications for subsequent atomisation

Wetherell,

Garmory

2024

Preprint

Self Cite

View full text Add to dashboard Cite

Prefilming airblast atomisers are commonly used in gas turbine combustion system fuel injectors. As the film propagates across the prefilmer it interacts with the high velocity gas stream above it. In this paper a numerical investigation into this interaction is presented. A Coupled Level Set \& Volume of Fluid method is used to simulate the development of the film along the KIT-ITS planar prefilmer (Gepperth et al., 2010). Initial results showed the importance of correctly specifying the contact angle as too high a value leads to the formation of rivulets instead of a continuous film. An analysis of the film and air showed two-way coupling. The presence of the film increases the growth rate of the gas phase boundary layer, and the strength and size of the turbulent structures within it. Surface waves form in the film, initially driven by the turbulent fluctuations, but developing into transverse waves. These waves are shown to be independent, stochastic events instead of a periodic wave system. At the trailing edge of the prefilmer the increased turbulence level in the air, the variations in the film thickness and the associated change in fuel mass flow and momentum will have large implications for the atomisation process and subsequent fuel spray. These will also impact simulation of the atomisation, as the boundary condition complexity is much greater than commonly used, and the variations will require larger domains and longer simulation times to obtain fully converged atomisation statistics.

show abstract

“…Fluid viscosity is also highly temperature dependant [22], for the example of water, as the temperature decreases the fluid viscosity increases exponentially. Additionally, G.Hodgson et al [23] demonstrated that salinity can more than double the dynamic viscosity of a fluid. Ethylene glycol, a commonly used antifreeze fluid in automotive industry has a dynamic viscosity an order of magnitude larger than that of pure water [24].…”

Section: An Application Of Hydrodynamic Lubrication Theory To Automot...mentioning

confidence: 99%

Quantitative Multi-Physics Tools for Automotive Wiper Design

Graham¹,

Knowles²,

Mavros³

2023

SAE Technical Paper Series

View full text Add to dashboard Cite

<div class="section abstract"><div class="htmlview paragraph">The primary function of automotive windscreen wipers is to remove excess water and debris to secure a clear view for the driver. Their successful operation is imperative to vehicle occupants’ safety. To avoid reliance on experimental testing there is a need to develop physics-based models that can quantify the effects of design-based decisions on automotive wipers. This work presents a suite of evaluative tools that can provide quantitative data on the effects of design decisions. We analyse the complex non-linear contact interaction between the wiper blade and the automotive screen using finite element analysis, assessing the impact of blade geometry on the contact distribution. The influence of the evolution of normal applied load by the wiper arm is also investigated as to how it impacts the contact distribution evolution. The dynamics of the blade are subsequently analysed using a multiple connected mass spring damper system. Additionally, we apply hydrodynamic lubrication theory to study the residual film thickness post wipe and assess the effect of wiper blade geometry and lubricant composition. Finally, the complete wiper system is studied using a lump dynamic model, and bifurcation analysis is applied to determine areas of instability due to friction induced vibrations. Additionally, the wiper dynamics modelling shows peak frequencies occurring at 30-50Hz, which agrees well with a documented range of chatter frequencies. The friction coefficients calculated within the hydrodynamic model fall within experimentally documented ranges of lubricated sliding friction, <i>μ</i> ≈ 0.1. Furthermore, the areas of operational stability predicted by our bifurcation model coincide with current experimentally determined optimal operational regions for automotive wipers.</div></div>

show abstract

Contact angle measurements for automotive exterior water management

Cited by 10 publications

References 42 publications

The Effect of Film Development on Primary Breakup in a Prefilming Airblast Atomizer

The Effect of Film Development on Primary Breakup in a Prefilming Airblast Atomizer

Air-film coupling in prefilming airblast atomisers and the implications for subsequent atomisation

Quantitative Multi-Physics Tools for Automotive Wiper Design

Contact Info

Product

Resources

About