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IBF Performance is split into two areas for analysis: Design Parameters and  

IBF Performance is split into two areas for analysis: Design Parameters and  

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An insight into the design parameters that dictate engine inlet barrier filter performance is presented. The work represents the first part of a two-part study into the factors affecting the performance of engine inlet barrier filter to ultimately enable the prediction of turboshaft engine performance during use of this air-particle separating devi...

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Citations

... Once the particulate has reached the engine, it will undergo changes in composition and bulk mass, due to filtration effects from the engine inlet protection system. Many helicopters are protected by a barrier filter or a vortex tube pack [14]; the T700 has an Inertial Particle Separator (IPS), which is integrated into the engine inlet. The degree of effectiveness of these systems depends on the particle size, or more accurately the Stokes number, of the particle-fluid-separator system. ...
... We also assumed that the particles are spherical and the particle Reynolds number does not exceed 800. Equation (14) does not account for the gradient and surface forces of thermophoresis, turbulent diffusion, Saffman's lift and adhesion forces, significant in the near-wall region. They are the dominant transport mechanisms for particles below a few microns in diameter, and require the boundary layer and turbulent kinetic energy to be modelled. ...
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... Numerical simulation is a powerful tool for pleated filter design because it can provide informative and reliable results [10][11][12][13][14]. In pleated fibrous filter, captured particles would deposit in filter medium or on filter surface [15][16][17]. ...
... Table 2 shows the computing time for different cases. The relative computing time is defined by Eq. (14). The computing time required by the Eulerian-Markov model was about 20% of that consumed by the Lagrangian model. ...
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Computational fluid dynamics (CFD) is a powerful tool for the design of pleated fibrous filters. The Lagrangian method is widely used to simulate particle motion, filtration and clogging in pleated filters. However, the Lagrangian method is very time-consuming because it tracks large number of particle trajectories. In order to overcome the disadvantages, the current study proposed a new Eulerian-Markov method. The Eulerian method and Markov chain model were utilized to simulate the particle concentration field in the air zone and filter medium of a pleated filter respectively. The hybrid method was validated by experimental results from previously published literature. It was found that the Eulerian-Markov method is accurate, time-saving and widely applicable. Compared to the Lagrangian method, the newly developed Eulerian-Markov method could reduce computing time by 80%–90%.
... As part of Reference [6], the interaction of the rotor with the intake flow field was investigated. To protect the engine in dusty and dirty environments, the effect of inlet barrier filters [7], engine inlet particle separators, such as scavengers [8] or foreign object damage grids, were investigated in detail. A study of a dynamic intake including an inertial separator was conducted as part of Reference [9]. ...
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... We modeled different transient dust clogging processes when the coefficient A was between 30 and 200. The pleat geometry and particle size used in the cases were from literatures Bojdo and Filippone 2011). The modeled total pressure drop increased linearly with the increase of coefficient A. The particle cake layer distribution was the same for the different cases. ...
... In the case with fixed pleat height, the high pleat density would increase the pressure loss by pleat channel due to viscous and inertial effects and decrease the pressure loss by larger filter medium area (Rebai et al. 2010b;Bojdo and Filippone 2011). So the optimal pleat density for air filter may exist. ...
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The dust loading has a significant influence on the transient performance of air filters. This study developed two models based on the Lagrangian and Eulerian methods to simulate the unsteady filtration process in the pleated filter. The flow field through the filter was calculated by solving the Navier-Stokes equation with the DES-SA turbulence model. The filter media and the cake layer were modeled as the porous zone. The Lagrangian method tracked the particle trajectories to model the particle motion, but the Eulerian model treated the particle as continuous phase. Two cell models were proposed to simulate the transient particle deposition and the cake layer growth on the filter medium surface for the Lagrangian and Eulerian methods, respectively. The simulated results were validated by the available experimental data. Both of the methods could provide relative accurate results with acceptable error. But the computing speed of Eulerian model was faster than the Lagrangian method. Otherwise, the new developed Eulerian model was used to investigate the effect of dust loading on the optimal design of pleated filter.© 2016 American Association for Aerosol Research
... While such high concentrations are common in baghouse cleaners, the space in the intake plenum, in which an IBF must fit, is far less accommodating than the almost limitless area afforded to the former. Consequently, a typical superficial velocity (volume flow rate divided by projected filter area) is in the region of 3 to 10 ms −1 [9], which translates to filtration velocities of the order 1 ms −1 . This is two orders of magnitude higher than the face velocities found in the studies by Lo et al. [3,5], and an order of magnitude higher than range used in the work of Fotovati et al. [16]. ...
... With respect to the field of helicopter engine protection, there are currently no studies in the literature that predict the performance of an installed IBF using CFD or analytical theory of pleats of this size, other than those published by the authors (see Refs. [9,10,11,12]). Of work pertaining to IBF, there are two notable contributions. ...
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An investigation into the efficacy of helicopter engine sand filters is conducted. Engine Air Particle Separation devices are broadly split into three categories: Vortex Tube Separators, Integrated Particle Separators, and Inlet Barrier Filters. The first two are inertial separators that scavenge particles by centrifugal force; the latter traps particles on its surface, but all three are designed with the aim or removing all particles from the engine bound air. Each technology is different, which gives rise to varying levels of efficacy. The current work uses low order analytical and numerical models to explore these differences and introduces a metric for quantifying the quality of air-particle separation performance. The vortex tube separators exhibit a high efficiency and low pressure drop, but require auxiliary power to operate and experience considerable drag at high forward speeds. Inertial particle separators do not achieve the high separation efficiencies of the vortex tubes or barrier filters, but have a large mass flow to frontal area ratio, hence low drag. Inlet barrier filters are highly efficient at removing particles and improve in this over time due to the accumulation of particles, but at the expense of a temporally increasing pressure drop. The new metric is a quality factor that can be used to directly compare separation technologies for helicopter. Its application is demonstrated by the inlet barrier filter which, when clean, is the best performing device, but over time deteriorates in quality due to the accumulation of particles.