for a long time, many efforts have been taken on improving gas turbine performance to increase the propulsive force and keep the chamber walls cool. in this regard, implementation of cyclonic and vortex engines have been proposed. according to increasing in the engine efficiency and keeping the chamber walls cool, the bidirectional vortex flow which is exited in the vortex engine, makes researc...

Unsteady forces generated by fluid flow through the impeller shroud leakage path of a centrifugal pump were investigated. The effect of leakage path inlet swirl (pump discharge swirl) on the rotordynamic forces was re-examined. It was observed that increasing the inlet swirl is destabilizing both for normal and tangential rotordynamic forces. Attempts to reduce the swirl within the leakage path...

The influence of the inlet swirl velocity profile shape on the decay of swirl in steady-state, incompressible, laminar pipe flows is investigated by means of computational fluid dynamics. The investigation is carried out for a Reynolds number of 2000, which marks the upper limit of the laminar flow behavior for unidirectional pipe flow. Computations are performed for two different mean swirl nu...

An investigation into in-cylinder swirl and tumble flow characteristics with reduced maximum valve lifts (MVL) is presented. The experimental work was conducted in the modified four-valve optical spark-ignition (SI) test engine with three different MVL. Particle image velocimetry (PIV) was employed for measuring in-cylinder air motion and measurement results were analyzed for examining flow fie...

Impinging jets are used in a wide number of industrial cooling applications due to their high heat and mass transfer abilities. The current research is concerned with the effect of swirl on the heat transfer characteristics of jet impingement cooling. Two inserts were designed order to generate swirling flow. These two designs, “Swirl Insert A” and “Swirl Insert B”, were tested at various Reyno...

Tidal stream turbines (TSTs) produce a rotating downstream wake. This paper describes the characteristics of the swirl flow in the wake of a TST with a view of comparing these against classical swirl theory and investigating whether swirl is an important factor in wake recovery prediction. Using computational fluid dynamics the paper describes the characteristics of velocities, pressure drop, v...

Flow watermarks are active traffic analysis techniques that help establish a causal connection between two network flows by content-independent manipulations, e.g., altering packet timings. Watermarks provide a much more scalable approach for flow correlation than passive traffic analysis. Previous designs of scalable watermarks, however, were subject to multi-flow attacks. They also introduced...

Increasing interest has been given to swirl brakes as a means of reducing destabilizing rotordynamic.forces due to leakage flows in new high speed rocket turbopumps. Although swirl brakes have been used successfully in practice {such as with the Space Shuttle HPOTP), no experimental tests until now have been pegormed to demonstrate their beneficial effect over a range of leakage flow rates. The...

This paper examines the manner in which heat release resulting from premixed combustion alters the nature of near-critical, axisymmetric, swirling flow in a straight circular pipe. Attention is confined to dilute premixtures so that exothermicity is weak and a small-disturbance approach applicable. The weak exothermicity is found to have a considerably larger effect on the flow. In the absence ...

a newly developed heavy duty diesel engine in dual fuel mode of operation has been studied in detail. the main fuel would be natural gas and diesel oil as pilot injection. the importance and effects of mixture preparation and formation through ports, valves and in cylinder flow field with different swirl ratio and tumble on diesel combustion phenomena is an accepted feature which has been studi...