Side Thrust Control by Secondary Gas Injection into Rocket Nozzles

1968 ◽  
Vol 10 (3) ◽  
pp. 239-251 ◽  
Author(s):  
J. H. Neilson ◽  
A. Gilchrist ◽  
C. K. Lee
Keyword(s):  
Secondary Flows ◽  
Axial Thrust ◽  
Side Force ◽  
Axial Location ◽  
Force Transducers ◽  
Directional Control ◽  
Constant Diameter ◽  
Supersonic Region ◽  
Thrust Control ◽  
Secondary Port

Directional control of rockets can be achieved by using secondary gas jets for providing side forces. The present investigation is concerned with the fact that a greater side force can be achieved by expanding the secondary gas into the supersonic region of the main nozzle than by expanding it directly to atmosphere. A laboratory test rig using ambient temperature air for the primary and secondary flows is described. Axial thrust and side force were measured using strain gauge force transducers. The experiments were performed on a small axisymmetric main nozzle with a 10° semi-angle of divergence and with sonic injection through circular ports placed normal to the main nozzle axis. The investigations centred principally on the effects of (1) varying the secondary port size at a given axial location in the nozzle and of (2) varying the axial location of a port of constant diameter. Side force and axial thrust augmentation characteristics were obtained for a range of primary and secondary flow inlet pressures. The results show the relative importance of the parameters on which side force depends, the maximum side force that may be produced and the interdependence of axial thrust augmentation and side force.

Thrust Vector Control by Secondary Gas Injection in Two-Dimensional Nozzles

1968 ◽  
Vol 72 (685) ◽  
pp. 77-81 ◽  
Author(s):  
John H. Neilson ◽  
Alastair Gilchrist ◽  
Chee K. Lee
Keyword(s):  
Static Pressure ◽  
The Body ◽  
Two Dimensional ◽  
Nozzle Wall ◽  
Side Force ◽  
Wall Area ◽  
Conical Shock ◽  
Supersonic Region ◽  
Secondary Port ◽  
Point To Point

When side force is produced by the injection of a secondary gas into the supersonic region of an axi-symmetric nozzle, the body shape of the obstruction caused by the secondary flow induces a cone-shaped separation region upstream of the port. From the apex of the cone a conical shock front is developed. Part of the total side force produced is due to the excess static pressure acting on the nozzle wall in (a) the separated region, and in (b) the wall area lying between the separated region and the trace of the shock on the nozzle wall. In such a field the static pressure is not uniform downstream of the shock but varies from point to point on the nozzle wall areas in question. This aspect of axi-symmetric flow makes attempts to correlate theoretical and experimental work difficult. It was considered that basic information about the important parameters, which influence side force, could best be obtained in experiments with two-dimensional nozzles. Here the circular secondary port is replaced by a rectangular port, the separation zone is wedge-shaped, the shock has a plane front, and in theory, the static pressure is uniform between the port and the point at which the boundary layer separates.

Control Forces in Rocket Nozzles Produced by a Secondary Gas Stream Inclined at Various Angles to the Nozzle Axis

1969 ◽  
Vol 11 (2) ◽  
pp. 175-180 ◽  
Author(s):  
J. H. Neilson ◽  
A. Gilchrist ◽  
C. K. Lee
Keyword(s):  
Mass Flow ◽  
Axial Thrust ◽  
Side Force ◽  
Nozzle Axis ◽  
Upstream Direction ◽  
Supersonic Regime ◽  
Mass Flows ◽  
Secondary Port ◽  
Control Forces ◽  
Port Location

The side force produced by the injection of secondary gas into the supersonic regime of a main nozzle is investigated with particular reference to the effect of the angle between the secondary jet and the main nozzle axis. In the experiments, downstream and upstream injection angles at one secondary port location in the main nozzle were examined. It is shown that there is a definite advantage to be gained by injecting the secondary gas in an upstream direction. An analytical analysis of the results indicates that for moderate secondary mass flows maximum side force is produced when the angle between the axis of the secondary port and the normal to the axis of the main nozzle is in the range 40-50°. When injecting a given secondary mass flow at the angle for maximum side force the axial thrust augmentation is almost zero. As the angle of injection is reduced from upstream values to downstream values the side force reduces and the thrust augmentation increases, indicating that thrust augmentation can be used to determine how effectively a given mass flow of secondary fluid is being utilized in the production of side force.

scholarly journals Wavelet analysis of flame blowout of a liquid-fueled swirl burner with quarls

2019 ◽  
Vol 67 (5) ◽  
pp. 394-403
Author(s):  
Viktor Józsa ◽  
Gergely Novotni
Keyword(s):  
Wavelet Transformation ◽  
Acoustic Noise ◽  
Operating Regime ◽  
Pollutant Emissions ◽  
Swirl Number ◽  
Axial Thrust ◽  
Lean Blowout ◽  
Swirl Combustion ◽  
Thrust Control ◽  
Flame Shape

Lean swirl combustion is the leading burner concept today, used in several steadyoperating applications to ensure awide operating range and low pollutant emissions. Approaching lean blowout is highly desired by design to achieve the lowest possible NOX emission. It was shown earlier that quarls could significantly extend the operating regime of liquid-fueled swirl burners. In the present study, the accompanying acoustic noise is evaluated by continuous wavelet transformation to show the effect of various quarl geometries on lean flame blowout. However, the desired flame shape of swirl burners is V, first, and a straight flame, and then a transitory regime can be observed before the developed V-shaped flame through increasing the swirl number. If the axial thrust is excessive, blowout might occur in earlier stages. Presently, the characteristic bands before blowout were analyzed and evaluated at various quarl geometries, swirl numbers, and atomizing pressures. The latter parameter also acts as an axial thrust control to adjust the swirl number. firstly, a straight flame, then a transitory regime can be observed before the developed V-shaped flame through increasing the swirl number. If the axial thrust is excessive, blowout might occur in earlier stages. Presently, the characteristic bands before blowout were analyzed and evaluated at various quarl geometries, swirl numbers, and atomizing pressures. The latter parameter also acts as an axial thrust control to adjust the swirl number.

Axial Thrust Control of High-speed Centrifugal Pump with Cavity Vanes

2012 ◽  
Vol 15 (6) ◽  
pp. 46-50 ◽  
Author(s):  
Dae-Jin Kim ◽  
Chang-Ho Choi ◽  
Jun-Gu Noh ◽  
Jinhan Kim
Keyword(s):  
Centrifugal Pump ◽  
High Speed ◽  
Axial Thrust ◽  
Thrust Control

A Theory for the Side Force produced in Two-Dimensional Nozzles by Secondary Gas Injection

1968 ◽  
Vol 72 (687) ◽  
pp. 267-274
Author(s):  
John H. Neilson ◽  
Alastair Gilchrist ◽  
Chee K. Lee
Keyword(s):  
Gas Injection ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Three Dimensional Flow ◽  
Side Force ◽  
Dimensional Flow ◽  
Increase With Increase ◽  
Two Dimensional Flow ◽  
Secondary Port ◽  
Theoretical Side

Summary:This work is concerned with the side force produced in rocket nozzles by secondary gas injection. A new theory for determining the side force is presented for two-dimensional flow and this is considered to be an important step towards a theory applicable to three-dimensional flow. The proposed theory is based on a double wedge model for the separated region upstream of the secondary port. The principal feature of the model is that it accounts tor the fact that the angle of the shock wave, originating from the separated region, is observed to increase with increase in secondary mass flow rate. Theoretical side force results are shown to compare favourably with experimental results obtained using two-dimensional nozzles and a comparison is made between the proposed theory and the theories of other workers.

2nd Quadrant Centrifugal Compressor Performance: Part I

2016 ◽  
Author(s):  
Elisabetta Belardini ◽  
Dante Tommaso Rubino ◽  
Libero Tapinassi ◽  
Marco Pelella
Keyword(s):  
Centrifugal Compressor ◽  
Mechanical Design ◽  
Reverse Flow ◽  
Pressure Fluctuations ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Reverse Direction ◽  
Direct Flow ◽  
Axial Thrust ◽  
Validation Data

Performance curves in 2nd quadrant are important to size protection equipment of both compressor and surrounding system. With reverse flow also the level and frequency of pressure fluctuations in different operating points is important to estimate blade loading and possible presence of excitation frequencies. The capability of performance predictive tools (either CFD or correlations based methods) as also mechanical design criteria are generally poor in 2nd quadrant and suffer for the scarcity and inadequacy of validation data. The second quadrant branch for a centrifugal compressor has been experimentally tested after the standard characterization in direct flow. A test arrangement has been designed, with a booster compressor connected in parallel with the tested stage, forcing the flow to be stable in reverse flow. The compressor characteristics have been measured with static and dynamic instrumentation. Present experience showed that when machine is operated in the stable reverse flow condition, pressure fluctuations and vibration are higher with respect to the values measured in nominal direct flow operating conditions. The increase is in the order of 10–20% of the corresponding value in direct flow. The same can be stated also for axial thrust and secondary flows that increase when the gas flows in reverse direction but the increase is in the order of 10–15%. Thus in 2nd quadrant, compressor equipment (in particular impeller blades) and all other system devices experience unusual loading levels but the additional loads are not big enough to cause relevant damaging if sustained for limited time periods. This result may allow simplifying the design of system layout: in particular, if during ESD no surging cycle is expected but only a reverse flow sustained steadily by the system (which is actually the most typical experience), the additional ASV’s, such as hot or cold gas by-pass valves, may be reduced in size or eventually removed optimizing the plant BOP.

The Additional Side Force on the Force Transducer in the Combinatorial Load Cell

2014 ◽  
Vol 541-542 ◽  
pp. 1327-1332 ◽  
Author(s):  
Tie Ping Wei ◽  
Xiao Xiang Yang ◽  
Jin Hui Yao ◽  
Hang Xu
Keyword(s):  
Three Dimensional ◽  
Element Model ◽  
Force Transducer ◽  
Load Cell ◽  
Side Force ◽  
Thrust Bearings ◽  
Force Transducers ◽  
Dimensional Finite Element ◽  
Late Model ◽  
Three Dimensional Finite Element

By the reason of the additional side force acting on the force transducers affecting the rotation effect of the combinatorial load cell,the paper describes the effect of the spherical plain thrust bearings structure on the additional side force. A three-dimensional finite element model of the late-model high-accuracy combinatorial load cell was established and analyzed. From the results, it shows that the magnitude of the additional side force fluctuation increases with the height of the bearing base increasing. At the same time, the magnitude decreases with the friction coefficient of the inner and outer ring of bearing increasing. The results provide guidance for the design of the combinatorial load cell.

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