Fabric Filter Performance of Helicopter Inlet Barrier Filters

2012 ◽  
Vol 57 (3) ◽  
pp. 1-13 ◽  
Author(s):  
Nicholas Bojdo ◽  
Antonio Filippone
Keyword(s):  
Pressure Drop ◽  
Pressure Loss ◽  
Separation Efficiency ◽  
Engine Performance ◽  
Woven Fabric ◽  
Additional Restriction ◽  
Transient Pressure ◽  
Temporal Separation ◽  
Fabric Filter ◽  
Filter Performance

An inlet barrier filter system is integrated into the intake of a helicopter to perform the task of removing potentially harmful particles from engine-bound air. While performing a vital duty in the prolonging of engine life, their use may incur a loss of engine performance as a result of the pressure loss that is synonymous with air passing through a porous barrier. Furthermore, as particles collect on the filter they pose additional restriction to the flow of air, causing the pressure drop to increase over time. It is the objective of the present work to propose a low-order model to predict this transient pressure loss, in order that the performance of helicopters operating with inlet barrier filters may be analyzed. The contribution includes a model to predict the temporal separation efficiency of a woven fabric filter and the temporal change in pressure drop due to the buildup of particles on the filter.

scholarly journals Experimental study of the pressure loss in aero-engine air-oil separators

2017 ◽  
Vol 121 (1242) ◽  
pp. 1147-1161 ◽  
Author(s):  
A. Laura Cordes ◽  
B. Tim Pychynski ◽  
C. Corina Schwitzke ◽  
D. Hans-Jörg Bauer ◽  
A. Thiago P. de Carvalho ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rotational Speed ◽  
Pressure Loss ◽  
Metal Foam ◽  
Separation Efficiency ◽  
Air Mass ◽  
Aero Engine

ABSTRACTThe results of extensive experimental testing of an aero-engine air-oil separator are presented and discussed. The study focuses on the pressure loss of the system. Oil enters the device in the form of dispersed droplets. Subsequently, separation occurs by centrifuging larger droplets towards the outer walls and by film formation at the inner surface of a rotating porous material, namely an open-cell metal foam. The work described here is part of a study led jointly by the Karlsruhe Institute of Technology (KIT) and the University of Nottingham (UNott) within a recent EU project.The goal of the research is to increase the separation efficiency to mitigate oil consumption and emissions, while keeping the pressure loss as low as possible. The aim is to determine the influencing factors on pressure loss and separation efficiency. With this knowledge, a correlation can eventually be derived. Experiments were conducted for three different separator configurations, one without a metal foam and two with metal foams of different pore sizes. For each configuration, a variety of engine-like conditions of air mass flow rate, rotational speed and droplet size was investigated. The experimental results were used to validate and improve the numerical modelling.Results for the pressure drop and its dependencies on air mass flow rate and the rotational speed were analysed. It is shown that the swirling flow and the dissipation of angular momentum are the most important contributors to the pressure drop, besides the losses due to friction and dissipation caused by the flow passing the metal foam. It was found that the ratio of the rotor speed and the tangential velocity of the fluid is an important parameter to describe the influence of rotation on the pressure loss. Contrary to expectations, the pressure loss is not necessarily increased with a metal foam installed.

scholarly journals Self-cleaning barrier filter for rotorcraft engines

2014 ◽  
Vol 118 (1209) ◽  
pp. 1311-1328
Author(s):  
N. Bojdo ◽  
A. Filippone
Keyword(s):  
Pressure Drop ◽  
Pressure Loss ◽  
Separation Efficiency ◽  
Longitudinal Axis ◽  
Design Parameters ◽  
Initial Increase ◽  
Filtration Area ◽  
Protection Devices ◽  
Self Cleaning ◽  
Internal Particle

AbstractA parameter-based study of a novel self-cleaning barrier filter concept for rotorcraft engines is presented. Existing engine inlet barrier filters for rotorcraft achieve a high separation efficiency (up to 99% for a dust resembling a coarse test dust) at the expense of a pressure drop that increases over time. Other engine protection devices with invariant pressure loss signals cannot offer the same level of efficiency. Furthermore, inlet barrier filters are absent on rotorcraft with larger mass flow demands, due to larger filtration area required. This work proposes a solution that addresses each of these limitations, and establishes the parametric framework upon which such a design could be realised. The drum-shaped self-cleaning barrier filter is affixed to the engine inlet and spins about its longitudinal axis, such that each of its fibrous filter pleats can be cleaned once per cycle. An initial increase of pressure loss gives way to a period of sustained invariance. The key parameters are the internal particle capacity of the chosen filter medium and the speed of rotation. Other design parameters can be optimised to yield minimum pressure drop for given set of flow conditions.

scholarly journals Clogging sensitivity of flow distributors designed for radially elongated hexagonal pillar array columns: a computational modelling

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Farideh Haghighi ◽  
Zahra Talebpour ◽  
Amir Sanati-Nezhad
Keyword(s):  
Pressure Drop ◽  
Aspect Ratio ◽  
Contact Zone ◽  
Separation Efficiency ◽  
Fluid Dynamic ◽  
Computational Modelling ◽  
Channel Width ◽  
Fluid Distribution ◽  
Design Parameters ◽  
Pillar Array

AbstractFlow distributor located at the beginning of the micromachined pillar array column (PAC) has significant roles in uniform distribution of flow through separation channels and thus separation efficiency. Chip manufacturing artifacts, contaminated solvents, and complex matrix of samples may contribute to clogging of the microfabricated channels, affect the distribution of the sample, and alter the performance of both natural and engineered systems. An even fluid distribution must be achieved cross-sectionally through careful design of flow distributors and minimizing the sensitivity to clogging in order to reach satisfactory separation efficiency. Given the difficulty to investigate experimentally a high number of clogging conditions and geometries, this work exploits a computational fluid dynamic model to investigate the effect of various design parameters on the performance of flow distributors in equally spreading the flow along the separation channels in the presence of different degrees of clogging. An array of radially elongated hexagonal pillars was selected for the separation channel (column). The design parameters include channel width, distributor width, aspect ratio of the pillars, and number of contact zone rows. The performance of known flow distributors, including bifurcating (BF), radially interconnected (RI), and recently introduced mixed-mode (MMI) in addition to two new distributors designed in this work (MMII and MMIII) were investigated in terms of mean elution time, volumetric variance, asymmetry factors, and pressure drop between the inlet and the monitor line for each design. The results show that except for pressure drop, the channel width and aspect ratio of the pillars has no significant influence on flow distribution pattern in non-clogged distributors. However, the behavior of flow distributors in response to clogging was found to be dependent on width of the channels. Also increasing the distributor width and number of contact zone rows after the first splitting stage showed no improvement in the ability to alleviate the clogging. MMI distributor with the channel width of 3 µm, aspect ratio of the pillars equal to 20, number of exits of 8, and number of contact zones of 3 exhibited the highest stability and minimum sensitivity to different degrees of clogging.

scholarly journals Numerical Study of Thermal-Hydraulic Performance of a New Spiral Z-Type PCHE for Supercritical CO2 Brayton Cycle

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4417
Author(s):  
Tingting Xu ◽  
Hongxia Zhao ◽  
Miao Wang ◽  
Jianhui Qi
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Pressure Loss ◽  
Numerical Study ◽  
Hydraulic Performance ◽  
Optimal Structure ◽  
Original Structure ◽  
Brayton Cycle ◽  
Compact Structure ◽  
Spiral Angle

Printed circuit heat exchangers (PCHEs) have the characteristics of high temperature and high pressure resistance, as well as compact structure, so they are widely used in the supercritical carbon dioxide (S-CO2) Brayton cycle. In order to fully study the heat transfer process of the Z-type PCHE, a numerical model of traditional Z-type PCHE was established and the accuracy of the model was verified. On this basis, a new type of spiral PCHE (S-ZPCHE) is proposed in this paper. The segmental design method was used to compare the pressure changes under 5 different spiral angles, and it was found that increasing the spiral angle θ of the spiral structure will reduce the pressure drop of the fluid. The effects of different spiral angles on the thermal-hydraulic performance of S-ZPCHE were compared. The results show that the pressure loss of fluid is greatly reduced, while the heat transfer performance is slightly reduced, and it was concluded that the spiral angle of 20° is optimal. The local fluid flow states of the original structure and the optimal structure were compared to analyze the reason for the pressure drop reduction effect of the optimal structure. Finally, the performance of the optimal structure was analyzed under variable working conditions. The results show that the effect of reducing pressure loss of the new S-ZPCHE is more obvious in the low Reynolds number region.

High Speed Flow Through Wire Gauzes

1959 ◽  
Vol 63 (584) ◽  
pp. 474-475 ◽  
Author(s):  
P. G. Morgan
Keyword(s):  
Pressure Drop ◽  
Pressure Loss ◽  
High Speed ◽  
Static Pressure ◽  
Flow Conditions ◽  
High Speed Flow ◽  
Speed Flow ◽  
Wire Gauze ◽  
Flow Through

The Flow of Fluids through screens has been widely studied with particular importance being attached to the measurement of the pressure drop caused by a screen and its relation to the screen geometry and the flow conditions. The majority of the investigations have been carried out on wire gauze screens mounted in ducts with air passing through them, the static pressure being measured on either side of the gauze. Attempts have been made by Weighardt Annand and Grootenhuisto correlate the gauze geometry with the pressure drop and to enable the pressure loss over a given screen and with given flow conditions to be predicted.

Numerical Flow Simulation of Spacer Grids With Mixing Vanes in a 5 × 5 PWR Rod Bundle

2009 ◽  
Author(s):  
Moyse´s Alberto Navarro ◽  
Andre´ Augusto Campagnole dos Santos
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Pressure Loss ◽  
Considerable Increase ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Spacer Grid ◽  
Spacer Grids ◽  
Rod Bundle ◽  
Vane Angle

The spacer grids exert great influence on the thermal hydraulic performance of the PWR fuel assembly. The presence of the spacers has two antagonistic effects on the core: an increase of pressure drop due to constriction on the coolant flow area and increase of the local heat transfer downstream the grids caused by enhanced coolant mixing. The mixing vanes, present in most of the spacer grid designs, cause a cross and swirl flow between and in the subchannels, enhancing even more the local heat transfer at the cost of more pressure loss. Due to this important hydrodynamic feature the spacer grids are often improved aiming to obtain an optimal commitment between pressure drop and enhanced heat transfer. In the present work, the fluid dynamic performance downstream a 5 × 5 rod bundle with spacer grids is analyzed with a commercial CFD code (CFX 11.0). Eleven different split vane spacer grids with angles from 16° to 36° and a spacer without vanes were evaluated. The computational domain extends from ∼10 Dh upstream to ∼50 Dh downstream the spacer grids. The standard k-ε turbulence model with scalable wall functions and the total energy model were used in the simulations. The results show a considerable increase of the average Nusselt number and secondary mixing with the angle of the vane up to ∼20 Dh downstream the spacer, reducing greatly the influence of the vane angle beyond this region. As expected, the pressure loss through the spacer grid also showed considerable increase with the vane angle.

Experimental study of lubricant-derived ash effects on diesel particulate filter performance

2019 ◽  
pp. 146808741987457 ◽  
Author(s):  
Jun Zhang ◽  
Yanfei Li ◽  
Victor W Wong ◽  
Shijin Shuai ◽  
Jinzhu Qi ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Diesel Particulate Filter ◽  
Particulate Filter ◽  
Maximum Temperature ◽  
Particle Emissions ◽  
Diesel Particulate ◽  
Particulate Filters ◽  
Filter Performance ◽  
Soot Loading ◽  
Active Regeneration

Diesel particulate filters are indispensable for diesel engines to meet the increasingly stringent emission regulations. A large amount of ash would accumulate in the diesel particulate filter over time, which would significantly affect the diesel particulate filter performance. In this work, the lubricant-derived ash effects on diesel particulate filter pressure drop, diesel particulate filter filtration performance, diesel particulate filter temperature field during active regeneration, and diesel particulate filter downstream emissions during active regeneration were studied on an engine test bench. The test results show that the ash accumulated in the diesel particulate filter would decrease the diesel particulate filter pressure drop due to the “membrane effect” when the diesel particulate filter ash loading is lower than about 10 g/L, beyond which the diesel particulate filter pressure drop would be increased due to the reduction of diesel particulate filter effective volume. The ash loaded in the diesel particulate filter could significantly improve the diesel particulate filter filtration efficiency because it would fill the pores of diesel particulate filter wall. The diesel particulate filter peak temperature during active regeneration is consistent with the diesel particulate filter initial actual soot loading density prior to regeneration at various diesel particulate filter ash loading levels, while the diesel particulate filter maximum temperature gradient would increase with the diesel particulate filter ash loading increase, whether the diesel particulate filter is regenerated at the same soot loading level or the same diesel particulate filter pressure drop level. The ash accumulation in the diesel particulate filter shows little effects on diesel particulate filter downstream CO, total hydrocarbons, N2O emissions, and NO2/NO x ratio during active regeneration. However, a small amount of SO2 emissions was observed when the diesel particulate filter ash loading is higher than 10 g/L. The ash accumulated in the diesel particulate filter would increase the diesel particulate filter downstream sub-23 nm particle emissions but decrease larger particle emissions during active regeneration.

scholarly journals 3D Printing for Energy-Saving: Evidence from Hydraulic Manifolds Design

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2462 ◽  
Author(s):  
Jun-hui Zhang ◽  
Gan Liu ◽  
Ruqi Ding ◽  
Kun Zhang ◽  
Min Pan ◽  
...  
Keyword(s):  
High Pressure ◽  
Pressure Drop ◽  
Numerical Methods ◽  
3D Printing ◽  
Pressure Loss ◽  
Smooth Transition ◽  
Factorial Experiments ◽  
Space Requirement ◽  
Geometrical Features ◽  
Full Factorial

With the compact circuit layout and small size, hydraulic manifolds sometimes cause high pressure loss. The purpose of this paper is to investigate the pressure loss under different circumstances with various geometry features and present solutions to reduce pressure loss. The pressure loss performance is evaluated by both experimental and numerical methods. Verified by the experiments, the numerical simulations are qualified to depict the correct trend of the pressure drop. After the basic analysis of traditional passages, three novel forms are proposed, which are very hard to be manufactured by a common method. Furthermore, the geometrical features are selected optimally by means of full factorial experiments to balance the pressure loss and space requirement. Moreover, taking advantage of 3D printing, it is possible to build the passages in novel forms which are beyond the capacity of conventional manufacturing. Results show that the pressure loss can be reduced considerably by adopting a smooth transition, where the reduction can reach up to 50%.

Study on Characteristics and Operating Parameters of Axial Rotating Hydrocyclone

2009 ◽  
Author(s):  
Yan Xu ◽  
Zunce Wang ◽  
Fengxia Lv ◽  
Sen Li
Keyword(s):  
Pressure Drop ◽  
Laboratory Experiments ◽  
Separation Efficiency ◽  
Rotation Speed ◽  
Tangential Velocity ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Axial Rotation ◽  
Rotating Wall ◽  
Simulation Results

The axial rotation of the hydrocyclone affects its internal flow characteristics and separating effect directly, as some local applications require the static hydrocyclone rotates about its own axis. Based on CFD, velocity distribution in the axial rotating hydrocyclone is studied. It is shown that as the rotation speed increasing, the tangential velocity improves and its gradient reduces in free vortex region observably, while the radial velocity has an incremental trend in the section of the small cone. The laboratory experiments are carried out for the static hydrocyclone of disposal capacity of 4 m3/h at 100r/min ∼ 300r/min. The relationships among rotation speed, flowrate, pressure drop and separated efficiency are achieved, which agree well with the numerical simulation results. The results indicate that the disposal capacity of hydrocyclone subjected to the rotation wall can be more flexible than that with no-rotating wall, the scope of best disposal capacity gradually enlarges with the increase of rotation speed of wall. Appropriate rise of the rotation speed is favor of the separation efficiency at the steady flowrate, however the increase of the flowrate and rotation speed induces the growth of the hydrocyclone’s pressure drop correspondingly to some extent.

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