tip leakage loss introduces major part of losses of the rotor in axial gas turbines. therefore, the rotor blade tip has a considerable effect on rotor efficiency. to understand the flow physics of the rotor tip leakage, we solve the flow field for different tip platforms (passive flow control) and by considering coolant tip injection (active flow control). various blade tip configurations such ...

The present paper investigates the effects of the trapezoidal teeth labyrinth seal on the leakage amount in gas turbines. The influences of increasing the number of teeth from 1 to 6 with step 1 and the tip clearance s=0.5 to 7.5 mm on the leakage flow at different pressure ratios of PR=1.5, 2 and 2.5 are examined, comprehensively. The analysis is performed numerically using a Finite-Volume...

This paper investigates the effect of inserting a ring type barrier on leakage flow of brush seals with different bristles clearances (the distance between bristle pack tip and rotor surface). The ring is placed on both upstream and downstream sides of the bristles. An axisymmetric CFD model is employed to calculate radial pressure distribution along backing plate, axial pressure variation on r...

Tip leakage loss introduces major part of losses of the rotor in axial gas turbines. Therefore, the rotor blade tip has a considerable effect on rotor efficiency. To understand the flow physics of the rotor tip leakage, we solve the flow field for different tip platforms (passive flow control) and by considering coolant tip injection (active flow control). Various blade tip configurations s...

Increasing the combustion temperatures in a gas turbine engine to achieve higher efficiency and power output also results in high heat loads to turbine components downstream of the combustor. The challenge of adequately cooling the nozzle guide vane directly downstream of the combustor is compounded by a complex vortical secondary flow at the junction of the endwall and the airfoil. This flow t...

extended abstract abstract pressure management is an effective method for water demand management. for evaluation of the effects of pressure changes on leakage level of water networks, the favad equation is usually used. however, in this equation, exponent of pressure parameter (n) needs to be determined. for estimation of n, either some information about the leak opening is necessary or networ...

We present a survey of the work on control-flow analysis carried on by the Venice Team during the Mefisto project. We study security issues, in particular information leakage detection, in the context of the Mobile Ambient calculus. We describe BANANA, a Java-based tool for ambient nesting analysis, by focussing on analysis accuracy and algorithmic optimizations.

A rotary vane expander has been developed to replace the throttling valve for improving the COP of transcritical CO2 refrigeration system. Due to the serious internal leakage, the expander efficiency is not satisfactory. This paper presents the theoretical and experimental investigation on the internal leakage in a rotary vane expander prototype. Firstly, the leakage flow rate through the inter...

Characteristics of rotor blade tip clearance flow in axial compressors can significantly affect their performance and stable operation. It may also increase blade vibrations and cause detrimental noises. Therefore, this paper is contributed to investigate tip leakage flow in a low speed isolated axial compressor rotor blades row. Simulations are carried out on near-stall condition, which is val...