Fluid flow in labyrinth seals of a turbine engine is described. The aim is to describe numerical calculations of fluid flow in labyrinth seals and evaluate the calculated data for different settings of radial clearance of labyrinth seals. The results are achieved by 3D CFD detailed simulations in a typical seal geometry. The calculations are performed for different radial clearances at a constant pressure drop. The calculated data are evaluated based on mass flow, static pressure, total enthalpy and total temperature of air. Based on the calculated data, it is visible, that the total temperature of air is increased in the labyrinth seals. The static pressure of air acts as expected –the static pressure is decreased in all teeth. The Mach number is similar in all teeth, but the maximal maximum value is in the last tooth, because of the expansion into the ambient conditions. Results of the calculations are that the total temperature in labyrinth seals is not constant as it is usually presented or supposed usually in common literature.
The paper deals with results of measurements of forces acting on volleyball. Drag coefficients evaluated from measurements in two aerodynamic tunnels are compared. The other force components i.e. lift and side force obtained by experimental investigation with angle of attack related to the axis of rotation are studied.
The stereo PIV measurement were performed behind a wing in the plane perpendicular to the flow to study the vortical structures oriented in the streamwise direction, which take place both in suction and pressure sides of the wing. The Reynolds numbers during the experiments in the 3 m wind tunnel range from 0.5 million up to 1.5 million.
Purpose
Some recent effort showed that usage of Krueger flaps helps to maintain laminar flow in cruise flight. Such flaps are positioned higher relative to the chord to shield the leading edge from the insect contamination during take-off. The flap passes several through critical intermediate position during the deployment to its design position. The purpose of this paper is to analyse the aerodynamics.
Design/methodology/approach
To better understand such flow phenomena, the combined approach of computational fluid dynamics and experimental methods were used. Flow simulation was performed with in-house finite volume Navier–Stokes solver in fully turbulent unsteady RANS regime. The experimental data were obtained by means of force and pressure measurements and some areas of the flow field were examined with 2 C particle image velocimetry.
Findings
The airfoil with flap in critical position has a very limited maximum lift coefficient. The maximum achievable lift coefficient during the deployment is significantly affected by the vertical position of the trailing edge of the flap. The most unfavourable position during the deployment is not the flap perpendicular to the chord, but the flap inclined closer to it is the retracted position.
Research limitations/implications
The flap movement was not simulated either in the simulation or in the experiment. Only intermediate static positions were examined.
Practical implications
A better understanding of aerodynamic phenomena connected with the deployment of a Krueger flap can contribute to the simpler and lighter of kinematics and also to decrease time-to-market.
Originality/value
Limited experimental and computational results of Krueger flap in critical positions during the deployment are published in the literature.
This article presents the labyrinth seal radial clearance influence. A generic labyrinth seal of a turbine aircraft engine was modeled. The target is to compare and analyze the influence of the radial clearance and location of teeth. The results can be useful for designing the location of teeth and their appropriate setting, especially for materials engineering and engineering technology in general.
This paper deals with the early development of the Anuloid, an innovative disk-shaped VTOL aircraft. The Anuloid concept is based on the following three main features: the use of a ducted fan powered by a turboshaft for the lift production to takeoff and fly; the Coanda effect that is developed through the circular internal duct and the bottom portion of the aircraft to provide further lift and control capabilities; the adoption of a system of ducted fixed and swiveling radial and circumferential vanes for the anti-torque mechanism and the flight control. The early studies have been focused on the CFD analysis of the Coanda effect and of the control vanes; the flyability analysis of the aircraft in terms of static performances and static and dynamic stability; the preliminary structural design of the aircraft. The results show that the Coanda effect is stable in most of the flight phases, vertical flight has satisfactory flyability qualities, whereas horizontal flight shows dynamic instability, requiring the development of an automatic control system.
The stereo PIV measurement were performed behind a wing in the plane perpendicular to the flow to study the vortical structures oriented in the streamwise direction, which take place both in suction and pressure sides of the wing. The Reynolds numbers during the experiments in the 3 m wind tunnel range from 0.5 million up to 1.5 million.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.