CN2274699Y

CN2274699Y - Centripetal turbine wheel radial and combined flow

Info

Publication number: CN2274699Y
Application number: CN 96229516
Authority: CN
Inventors: 孙正柱; 孙敏超
Original assignee: Individual
Current assignee: Sun Minchao
Priority date: 1996-03-21
Filing date: 1996-03-21
Publication date: 1998-02-18
Anticipated expiration: 2006-03-21

Abstract

The utility model discloses a radial flow and combined flow type centripetal turbine impeller which can be used for a turbocharger of an internal-combustion engine (a diesel, a gasoline engine). The utility model has the technical proposal that the blade shape of the centripetal turbine impeller is geometrically molded by the reasonable selection of geometric angle magnitude of a blade inlet according to the characteristic of load operation, the geometric angle of the blade inlet is an acute angle between 20 DEG and 85 DEG, or an obtuse angle between 95 DEG and 160 DEG, and the efficiency of centripetal turbine stage in different load conditions can be substantially raised.

Description

A kind of radial-flow type and mixed-flow centripetal turbine impeller

The utility model relates to the centripetal turbine impeller in interior radial-flow turbocharger of internal-combustion engine (diesel engine, petrol engine) technical field and the combined flow turbine pressurized machine.

In the prior art, based on the intensity height, manufacturing process is simple and the consideration of the little aspects factor of rotary inertia, the centripetal turbine impeller of radial-flow turbocharger and combined flow turbine pressurized machine all adopts footpath---axial flow type semi-open type or unshrouded impeller, and impeller inlet how much angles of blade shape employing blade import partly are 90 ° Mechanical Builds.Obviously, the gross differences that this operation characteristic of ignoring the internal-combustion engine different load causes impeller inlet fluid inlet angle value and excursion, the same impeller configuration that is limited to 90 ° admittedly of selecting with how much angles of blade import, will inevitably be under most of load conditions, produce the big angle of attack and impact loss, cause turbine efficiency obviously to reduce.The load operation characteristics of internal-combustion engine, promptly the power of internal-combustion engine and rotating speed have determined the quantitative relation of pressurized machine centripetal turbine impeller inlet fluid inlet angle with load variations with the relation of load variations.According to the concrete load condition of each boosting explosive unit, can make the corresponding relation of impeller inlet flow angle and load variations, and determine the magnitude variations scope at impeller inlet air flow angle under the operating mode scope situation commonly used thus.On the other hand, gas dynamical theory of centripetal turbine and experiment are pointed out: for how much angles of each blade import, all have a best flow angle that flows into impeller corresponding.Because relative vortex pair flows into the result of airflow direction generation " slippage " effect of impeller in the high-speed rotating impeller, make the best flow angle that flows into impeller not identical with blade import geometry angles.When the flow angle that flows into impeller departs from best flow angle, just produce the angle of attack and impact loss.The situation of flow separation on the size of the angle of attack decision blade face, the angle of attack is big more, and impact loss is big more, and the impact loss of high incidence is much bigger during than the equivalent negative angle of attack.The angle of attack is very big to the decline influence of turbine efficiency, and it is the most important factor that influences turbine off-design efficiency value.The impeller that equals 90 ° for blade import how much angles, the best flow angle of the inflow impeller of determining according to the slip coefficient formula is about 115 °.Therefore, to equal 90 ° the most suitable load of centripetal turbine impeller be to make the design conditions fluid inlet angle of impeller inlet or the average fluid inlet angle of operating mode scope commonly used be 115 ° load at blade import how much angles.

The purpose of this utility model is in order to reduce the angle of attack and the impact loss of centripetal turbine impeller under design conditions or operating mode scope situation commonly used, to improve turbine efficiency, designing the centripetal turbine impeller of a kind of radial-flow type and combined flow turbine pressurized machine.

The utility model realizes that the technical conceive of above-mentioned purpose is by blade, wheel disc and wheel cap centripetal turbine impeller cast in block.Make the design conditions fluid inlet angle of turbine wheel or the average fluid inlet angle of operating mode scope commonly used according to load, determining that by corresponding slip coefficient formula how much angles of blade import of impeller carry out the geometric modeling of impeller blade shapes as the best flow angle that flows into impeller with this, is 20 °≤β of acute angle to how much angles of blade import of the Vehicular internal combustion engine turbosupercharger centripetal turbine impeller of normal operating mode scope low speed, low-load region operation the Maximum Torque operating mode near _1A≤ 85 °; Near how much angles of the blade import of the turbosupercharger that internal-combustion engine is used normal operating mode scope declared working condition are the 95 °≤β in obtuse angle _1A≤ 160 °.

The good effect that the utility model produces is to have eliminated because of what the impeller that adopts how much angles of blade import to equal 90 ° brought to realize the constraint and the limitation of high efficiency coupling to indivedual loads, and expands the high efficiency coupling to whole load conditions.The utility model since choose reasonable the value at blade import how much angles, the appearance and the whole angle of attack mean value that has reduced operating mode scope commonly used of high attack angle have been avoided, thereby make inlet blade angle equal 90 ° under the inapplicable load condition of impeller the centripetal turbine level and the efficient of whole turbosupercharger increase substantially, performances such as the oil consumption of internal-combustion engine, row temperature, moment of torsion obviously improve.

Below, with accompanying drawing technology contents of the present utility model is narrated explanation in conjunction with the embodiments.

Fig. 1 is how much angle β of centripetal turbine impeller blade import _1ADefinition figure.How much angle β of the blade import of centripetal turbine impeller _1AThe center line 2 that is blade profile 3 on the leaf runner geometrical center turning surface is at the tangent line 1 at import leading edge place and the angle between the peripheral velocity negative direction.

The turbosupercharger centripetal turbine impeller that is suitable near the low speed of the operating mode scope commonly used Maximum Torque operating mode, low-load region operation shown in Figure 2, how much angles of blade import are the topology view of acute angle when 20 °≤β (A)≤85 ° of scope situation.Object lesson shown in the figure is the semi-open type mixed flow turbine impeller shape that how much angles of a blade import equal 50 °.

Near the internal-combustion engine turbocharger turbine impeller of operating mode scope declared working condition commonly used that is suitable for shown in Figure 3, how much angles of blade import are that the obtuse angle is at 95 °≤β _1ATopology view during≤160 ° of scope situations.Object lesson shown in the figure is the enclosed radial-flow turbine impeller shape that how much angles of a blade import equal 120 °.

The blade 5 that Fig. 2 illustrates the semi-open type turbine wheel is cast as one with wheel disc 6, how much angle β of blade import _1ABe 50 °, be applicable to the turbosupercharger that the Vehicular internal combustion engine of near the slow-speed of revolution of the operating mode scope commonly used Maximum Torque operating mode, low-load region operation is used.The load change of Vehicle Turbocharged internal-combustion engine is frequent, supercharging level is generally not high, when above-mentioned operating mode scope commonly used is moved, the speed ratio of centripetal turbine level and rotating speed are all lower, the impeller inlet flow angle is very little, have only how much little impellers in angle of the blade of employing import could reduce high incidence and reduce impact loss maintenance high efficiency, structure of the present utility model can satisfy these needs just.The impeller that equals 90 ° with blade import how much angles is compared, because the big high incidence impact loss when having reduced the slow-speed of revolution, running on the lower load significantly, changes and originally expends in the idle work of impact loss to be effective merit, secondary speed is significantly increased.And the increase of secondary speed has caused the minimizing of high incidence and impact loss again, causes secondary speed further to increase, and the result forms benign cycle.The shortcoming and the disadvantage that to help to overcome that present Vehicular internal combustion engine ubiquitous acceleration of turbosupercharger when the slow-speed of revolution, low-load region operation is poor, negative pressure appear in variable working condition low-response and blower outlet.Cross the Maximum Torque operating mode when continuing to raise rotating speed when the operation of internal-combustion engine, the negative angle of attack appears in the import meeting of turbine wheel, and it is increasing to increase the negative angle of attack with rotating speed again.Because the negative angle of attack makes impact loss increase very limitedly; in addition to the high rotating speed operating mode of Vehicular internal combustion engine and do not require that the efficient of pressurized machine is high as far as possible; according to joining confidential asking; under the external characteristics operating mode; supercharging superpressure, pressurized machine hypervelocity also will be opened the exhaust by-pass valve venting usually when preventing high rotating speed, deliberately waste the available energy of a part of exhaust; therefore, favourable on the contrary with big negative angle of attack state operation in high rotating speed operating mode scope to restriction supercharging superpressure and supercharger rotor hypervelocity.The how much bending blade shapes of angle in 20 ° of-85 ° of scopes that inlet part of the present utility model forms, make in blade passage, turns all the same pressure side 4 that points to blade 5 of action direction of normal inertial force of generation of centrifugal inertia force that the impeller high speed rotating produces and inlet air flow with Coriolis inertial force, effectively suppress, retrained the expansion of flow separation on the blade pressure surface 4 that the negative angle of attack causes, greatly reduced the impact loss of the negative angle of attack.Equal 90 ° impeller than inlet blade angle and be more suitable for operating mode work at the negative angle of attack, its efficient is much higher.

The blade 5 that Fig. 3 illustrates enclosed radial-flow turbine impeller is cast as with wheel disc 6 and wheel cap 7 and is made into integration closed type structure.About 120 ° of how much angles of blade 5 imports are applicable to the turbosupercharger that near the internal-combustion engine of operating mode scope declared working condition commonly used used.The centripetal turbine impeller that equals 90 ° with how much angles of blade 5 imports is compared, and the speed ratio that the utility model is suitable for is higher, size is littler, is more suitable for working in high incidence operating mode scope.In the above-described embodiment, the semi-open type and the open type centripetal turbine blade wheel structure that adopt, as long as the intensity nargin of impeller and the restriction of wheel rotation inertia allowed, then this structure that turbosupercharger now generally should be adopted makes the double shrouded wheel structure into, so that the efficient of centripetal turbine level obtains further to improve.

Claims

1, a kind of radial-flow type and mixed-flow centripetal turbine impeller, it includes wheel disc (6), wheel cap (7) and blade (5), it is characterized in that the scope at how much angles of blade (5) import is 20 °-85 ° or 95 °-160 °.