Angle Vane Research Articles

Comparison of wind speed models within a Pitot-free airspeed estimation algorithm using light aviation data

This paper presents an analytical redundancy-based approach to the estimation of the true aircraft airspeed without the use of a Pitot probe. Measurements from an Inertial Measurement Unit (IMU), Global Positioning System (GPS), and angle of attack and sideslip angle vanes are used within a sensor fusion algorithm utilizing the kinematic model of a fixed-wing aircraft to co-estimate the airspeed, wind speed, and attitude of an aircraft. The presented model does not use information relative to the aircraft dynamic model, and therefore, is totally independent of the specific aircraft. Due to the necessity of the algorithm to determine the aircraft wind speed, a predictive model of the wind behaviour is necessary. This work compares two different stochastic wind models – the random walk (RW) and the Gauss–Markov (GM)–within the context of the airspeed estimation problem using flight data of a light aviation aircraft. The use of light aviation data is an important new consideration since previous work has focused on unmanned aircraft. The results of this study indicated that the RW model provides better performance over the GM model for airspeed estimation. Additionally, the light aviation data further reinforces the cross-platform capability of the considered algorithm and, furthermore, demonstrates the effectiveness of this method within manned flight.

Flame stability limits of low swirl burner − Effect of fuel composition and burner geometry

The stability of turbulent non-premixed biogas flame was studied experimentally by varying the fuel composition (i.e., changing the carbon dioxide content in the fuel, which is mainly composed of CH4 and CO2) and altering the fuel nozzle geometry. The fuel was discharged through a central nozzle surrounded by a co-axial airflow passing through a low-swirl (25°-angle vanes) generator. The results revealed that the biogas flame stability limits are highly sensitive to fuel composition in that a small increase in carbon dioxide content can lead to a significant shrinkage in the flame stability operating conditions. On the other hand, the results showed that the fuel jet momentum (fuel nozzle geometry) plays a key role in reducing the dependency of the stability of swirling non-premixed flame on fuel composition. The experimental data with varying both the fuel composition and fuel nozzle geometry was used to develop semi-empirical non-dimensional correlations capable of describing both the lower and upper flame stability limits of both biogas and methane fuel. The validity of these correlations was extended to include both non-premixed and premixed swirling flames.

CFD simulation of flow around angle of attack and sideslip angle vanes on a BAe Jetstream 3102 – Part 1

CFD modelling techniques are exploited to investigate the local velocity field around angle of attack and sideslip angle sensors fitted to the nose of a modified BAe Jetstream 3102 small airliner. Analysis of the flow angularity at the vane locations has allowed the vanes response to varying flight conditions to be predicted and errors in the readings to be quantified. Subsequently, a more accurate calibration of the system is applied to the current configuration on the Jetstream, and a better understanding of the position error with respect to the vane locations is obtained.The above aircraft was acquired by Cranfield University in 2003 with subsequent flow angle vane modifications taking place in 2005. The aircraft is currently in operation with the National Flying Laboratory Centre (NFLC) for research and demonstration purposes.

CFD simulation of flow around angle of attack and sideslip angle vanes on a BAe Jetstream 3102 – Part 2

A previous study analysing the local flow around angle of attack and sideslip angle vanes on a BAe Jetstream 3102 turboprop is extended to study the additional effects of bank angle. A full matrix of CFD simulations is carried out to investigate how the introduction of a bank angle affects vane performance for a range of flight conditions. An updated calibration method to convert the raw vane readings into true values of angle of attack and sideslip, incorporating a correction factor as a function of the bank angle, is presented. The results are shown to be accurate for a wide range of flight configurations. Uncertainty analysis indicates that raw vanes reading errors should be below ±0.1° to ensure that total calibration errors are restricted to less than 2% for angle of attack and 5% for sideslip angle.

Enhancing the Stability Limits of Biogas Non-Premixed Flame

ABSTRACTThe effect of fuel nozzle geometry on the stability of a low swirl non-premixed biogas flame has been examined experimentally. Fuel nozzle geometry was varied by changing its diameter or the number of peripheral holes/slots, while keeping constant the total cross-sectional area. In addition, the effect of the nozzle slot discharge angle was investigated. A low-swirl strength (25°-angle vanes) was used in the co-airflow, and the biogas fuel composition was kept constant (60% CH4 and 40% CO2 by volume). The results revealed that the swirl is essential for stabilizing a turbulent non-premixed biogas lifted flame. More importantly, fuel nozzle was found to influence drastically both the attached and lifted biogas flame stability limits. Finally, semi-empirical correlations have been proposed to describe the lifted biogas flame blowout limits.

Non-Premixed Turbulent Biogas Flame: Effect of The Co-Airflow Swirl Strength on the Stability Limits

This experimental study reports on the effect of swirl strength on the stability of non-premixed biogas flame. The swirl strength was varied by changing the vanes angle (25° and 50°) of the swirl generator. Zero-angle vanes swirl was also used as a reference. The results revealed that the swirl enhances significantly the biogas flame stability operating range. In addition, it was found that the biogas flame behaves differently depending on the swirl strength. The effect of low (25°-angle vanes) swirl on the flame stability was found to depend upon the co-airflow exit velocity. At low co-airflow velocity, the flame was attached and its blow-off limits are comparable to those of the zero (0°-angle vanes) swirl. However, as the co-airflow velocity increases, the low swirl attached flame lifts-off the burner and stabilizes over a wide range of co-airflow and fuel jet velocity. In contrast to low-swirl, high (50°-angle vanes) swirl generates only an attached biogas flame regardless of the co-airflow velocity. Moreover, the high swirl attached flame was found to stabilize over a wider range of flow conditions compared to that of low swirl. Particle image velocimetry (PIV) data were used to explain the stability limits and empirical correlations were proposed to describe these limits.

Ultrafiltration of macromolecules using rotating disc membrane module (RDMM) equipped with vanes: Effects of turbulence promoter

Reduction in the permeate flux is a major fundamental problem in membrane separation process due to membrane fouling and concentration polarisation. To alleviate these scenarios with an objective to attain proper throughput from the membranes, different types of high-shear devices have been proposed in literatures. In the present work with the rotating disc membrane module (RDMM), a high-shear device, vanes with different geometries and arrangements were used as turbulence promoters. The aim of the work is to identify a vane which will be worthy to obtain moderate permeate flux at the expense of low energy consumptions, i.e. with low applied trans-membrane pressure (TMP) and low membrane speed. To meet the objective a simulated solution of bovine serum albumin (BSA) and glucose was introduced as feed to the rotating disc membrane module (RDMM) fitted with different arrangements of vanes at different combinations of trans-membrane pressure (TMP), feed concentration and membrane speed. It was found that 45° blade angle vane having holes on the blade surface produce maximum permeate flux at low TMP and membrane speed for even high concentration of the feed solution, and thus responsible for the low rejection of glucose on the retentate side confirming maximum purity of BSA and glucose in either side of the membrane. ANOVA analysis was also done on the throughput of this vane to understand the effects of different operating parameters and the effect due to their mutual interactions.

MODELLING OF LOCAL SCOUR AROUND RECTANGULAR SUBMERGED VANE

ABSTRACT At optimal angle of attack, occurrence of destabilizing local scour phenomenon especially around the leading edge of the vane is formed and at this angle vane induced secondary circulation is also maximum. The maximum scour depth around the vane mainly depends on flow depth and flow Froude number. Flow Froude number is more important than Densimetric Froude number. This will presuppose checking the magnitude of local scour around the submerged vanes by a suitable local scour retarder method.

The Effect of a Downstream Rotor on the Measured Performance of a Transonic Turbine Nozzle

Two nozzle designs, involving the same low aspect ratio, high turning angle vanes, and differing in outer wall contour, were tested over a range of exit Mach numbers up to supersonic values. The experiments were conducted on a large-scale, full annular configuration with and without a representative rotor downstream. Nozzle performance was found to be significantly affected by rotor operation, the influence depending on the detailed characteristics of the nozzle flow field, as well as on the design and operation of the rotor itself. It is suggested that performance evaluation of low aspect ratio nozzles of high turning angle may require appropriate testing with a rotor.

Month in the Patent Office

An aircraft capable of horizontal flight as an aeroplane, and of vertical take off and descent, as well as vering, in the manner of a helicopter, consists of an ofoil‐shaped body 1 of approximately elliptical in form, having the major axis disposed trans‐sely and with a well portion 8 in which are mounted riable‐pitch contra‐propellers 7 driven by an engine the flow of air through the well being controlled louvres 10, 11 on the upper and lower surfaces pectively of the body 1. The axis of the propellers tilted forwardly at a small angle and transverse ide vanes 65 direct air from an inlet 9 into the spellers. When in horizontal flight the louvres 10, are closed and the propellers force the air rear‐rdly, while for vertical flight the louvres are ened so that the airflow through the body is ostantially vertical. In addition to the normal ntrol surfaces, rudder 13, elevators 16 and ailerons , the pitches of the propellers are capable of ferential adjustment to produce an unbalanced or torque to assist the rudder. When operating as a icoptcr additional control is provided by two pairs diametrically disposed segmental sliding covers , 19 which can be operated to close parts of the ening formed by the lower louvres 11.