CN115292934B - Design method for eccentric intersecting of bypass branch and main pipe of two-stage turbocharging system - Google Patents
Design method for eccentric intersecting of bypass branch and main pipe of two-stage turbocharging system Download PDFInfo
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- CN115292934B CN115292934B CN202210943104.0A CN202210943104A CN115292934B CN 115292934 B CN115292934 B CN 115292934B CN 202210943104 A CN202210943104 A CN 202210943104A CN 115292934 B CN115292934 B CN 115292934B
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- 238000013461 design Methods 0.000 title claims abstract description 17
- 238000000034 method Methods 0.000 title claims abstract description 13
- 238000004364 calculation method Methods 0.000 claims abstract description 12
- 230000003068 static effect Effects 0.000 claims description 7
- 238000009413 insulation Methods 0.000 claims description 3
- 238000004088 simulation Methods 0.000 claims description 3
- 230000000694 effects Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000004134 energy conservation Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
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Classifications
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
- F02B37/12—Control of the pumps
- F02B37/18—Control of the pumps by bypassing exhaust from the inlet to the outlet of turbine or to the atmosphere
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/08—Thermal analysis or thermal optimisation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Abstract
A design method for eccentric intersecting of a bypass branch and a main pipe of a two-stage turbocharging system in the technical field of turbocharging comprises the following steps: an air inlet of the high-pressure turbine is communicated with an engine exhaust manifold, and an air outlet of the high-pressure turbine is connected with an air inlet of the low-pressure turbine; an air inlet of a bypass branch pipe is communicated with an engine exhaust manifold, an air outlet of the bypass branch pipe is communicated with an interstage main pipe in front of a low-pressure turbine, and a bypass valve is arranged on the bypass branch pipe; the joint of the bypass branch pipe and the interstage main pipe is respectively designed to be left-biased, unbiased and right-biased; and the influences of left deviation, unbiased deviation and right deviation on the efficiency of the low-pressure stage turbine are respectively measured through an isentropic efficiency calculation formula of the low-pressure stage turbine, and a finally adopted design scheme is determined. The method is simple and effective, has wide application, and can bias the bypass branch pipes of different adjustable two-stage turbocharging systems and even multi-stage turbocharging systems, thereby achieving the purpose of improving the efficiency of the low-pressure stage turbine.
Description
Technical Field
The invention relates to a design method in the technical field of turbocharging, in particular to a design method for eccentric intersection of a bypass branch and a main pipe of a two-stage turbocharging system, which can improve the efficiency of a low-pressure turbine.
Background
With the increasingly stricter emission regulations and the further deepening of the concepts of energy conservation and emission reduction, the engine is continuously developed in the directions of high efficiency, energy conservation, cleanness and low carbon. The two superchargers are connected through the bent pipe and the bypass valve with adjustable opening degree to realize the optimal distribution of load, and the two superchargers have the advantages of high supercharging, wide flow range, high emphasis capacity, high efficiency and the like, and become an advanced turbocharging technology widely applied to a new generation of power devices.
The adjustable two-stage supercharging system has high structural compactness due to the influence of miniaturization of the engine, and has complex pipeline structures such as a bent pipe, a bypass branch pipe and the like with high torsion and severe steering between two turbines, and the flow in the whole pipeline system is more complex compared with the traditional single-stage turbocharging. Because of the structural characteristics, different forms of flow distortion exist in the interstage pipeline of the two-stage supercharging system and the inlets and outlets of the high-pressure turbine and the low-pressure turbine, so that the flow in the pipeline is more complex. The complexity of the flow field can cause changes in the aerodynamic performance of the turbine, further affecting the performance of the turbocharger system and thus the overall engine. Research shows that a certain degree of coupling effect exists between two-stage turbines in the two-stage adjustable supercharging system, one of the expression forms is that the rotational flow of the outlet of the high-pressure turbine affects the performance of the low-pressure turbine, and compared with the turbine inlet condition of steady-state uniform direct current, the rotational flow effect of the outlet speed field of the high-pressure turbine affects the efficiency of the low-pressure turbine by about 2% -3%.
Disclosure of Invention
The invention provides a design method for eccentric intersecting of a bypass branch pipe and a main pipe of an adjustable two-stage turbocharging system, aiming at the defects of the prior art, when a bypass valve is in a fully-opened state, deflection positions of bypass pipelines on an interstage main pipe are adjusted for high-pressure-stage outlet rotational flows with different directions, the flowing form of air flow at an inlet pipeline of a low-pressure-stage turbine is changed, and the effect of enhancing or inhibiting rotational flows is achieved, so that the pneumatic efficiency of the low-pressure-stage turbine is changed.
The invention is realized by the following technical scheme: the invention comprises the following steps:
the method comprises the steps that firstly, an air inlet of a high-pressure stage turbine is communicated with an engine exhaust manifold, and an air outlet of the high-pressure stage turbine is connected with an air inlet of a low-pressure turbine through an interstage main pipe;
step two, an air inlet of a bypass branch pipe is communicated with an engine exhaust manifold, an air outlet of the bypass branch pipe is communicated with an interstage main pipe in front of a low-pressure turbine, and a bypass valve is arranged on the bypass branch pipe;
step three, respectively carrying out left-offset, unbiased and right-offset designs on the joint of the bypass branch pipe and the interstage main pipe, and respectively carrying out simulation calculation on the three designs under the condition that the bypass valve is fully opened;
and step four, respectively measuring the influence of left deviation, unbiased deviation and right deviation on the efficiency of the low-pressure stage turbine by using an isentropic efficiency calculation formula of the low-pressure stage turbine, and determining a finally adopted design scheme.
Further, in the present invention, the isentropic efficiency calculation formula of the low pressure stage turbine is:
wherein T is t-in The total temperature of the inlet of the turbine is given by the unit K; t (T) s-out The turbine outlet static temperature is given by the unit K; p (P) t-in The total pressure is the total pressure of the inlet of the turbine, and the unit Pa; p (P) s-out The unit Pa is the turbine outlet static pressure; gamma is the non-dimensional air insulation coefficient and takes the value of 1.353.
The invention mainly comprises an interstage main pipe, a bypass branch and a low-pressure stage turbine, wherein the interstage main pipe is a main flow pipeline between the high-pressure stage turbine and the low-pressure stage turbine, and the bypass valve is equivalent to a bypass branch pipe for directly introducing air flow into an inlet pipeline of the low-pressure stage turbine from an exhaust main pipe. The bypass valve is divided into a full-open valve state and a full-closed valve state, and the flowing state and the distribution form of air flow in the pipeline are changed through opening and closing of the valve, so that the aerodynamic performance of the low-pressure stage turbine is changed. When the bypass valve is fully closed, the air flow of the exhaust manifold flows into the high-pressure stage turbine, the interstage main pipe and the low-pressure stage turbine in sequence. At the moment, the outlet rotational flow of the high-pressure stage turbine directly enters the low-pressure stage turbine after further development in the interstage main pipe; when the bypass valve is fully opened, one branch of the exhaust manifold directly flows into the bypass branch pipe, and is converged with the high-pressure stage outlet rotational flow at the junction position of the bypass branch pipe and the interstage main pipe, and the two air flows are mutually mixed and act to form a low-pressure stage turbine inlet flow form completely different from that when the valve is closed. The aerodynamic efficiency of a turbine as a fluid machine rotating at high speed is greatly affected by the internal fluid flow conditions, and changes in turbine inlet flow conditions tend to cause changes in turbine efficiency. The isentropic efficiency change of the low pressure stage turbine is used to measure the effect of the eccentricity of the bypass branch.
Compared with the prior art, the invention has the following beneficial effects: the method is simple and effective, has wide application, and can bias the bypass branch pipes of different adjustable two-stage turbocharging systems and even multi-stage turbocharging systems, thereby achieving the purpose of improving the efficiency of the low-pressure stage turbine.
Drawings
FIG. 1 is a schematic view of a bypass branch pipe according to an embodiment of the present invention;
FIG. 2 is a schematic view of an unbiased bypass branch in an embodiment of the present invention;
FIG. 3 is a schematic diagram of a left-hand offset structure of a bypass branch pipe according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a right-hand offset bypass branch in an embodiment of the present invention;
FIG. 5 is a graph illustrating low pressure stage turbine efficiency variation for various eccentric modes in an embodiment of the present invention.
Wherein 1 is an interstage main pipe, 2 is a bypass branch pipe, and 3 is a low-pressure stage turbine.
Detailed Description
The following describes embodiments of the present invention in detail with reference to the accompanying drawings, and the embodiments and specific operation procedures of the present invention are given by this embodiment on the premise of the technical solution of the present invention, but the protection scope of the present invention is not limited to the following embodiments.
Examples
1-5, an air inlet of a high-pressure stage turbine is communicated with an engine exhaust manifold, and an air outlet of the high-pressure stage turbine is connected with an air inlet of a low-pressure turbine 3 through an interstage main pipe 1; the air inlet of the bypass branch pipe 2 is communicated with an engine exhaust manifold, the air outlet of the bypass branch pipe 2 is communicated with an interstage main pipe 1 in front of a low-pressure turbine, and a bypass valve is arranged on the bypass branch pipe 2; respectively carrying out left deviation, unbiased and right deviation designs on the joint of the bypass branch pipe and the interstage main pipe, and respectively carrying out simulation calculation on the three designs under the condition that the bypass valve is fully opened; and the influences of left deviation, unbiased deviation and right deviation on the efficiency of the low-pressure stage turbine are respectively measured through an isentropic efficiency calculation formula of the low-pressure stage turbine, and a finally adopted design scheme is determined.
The isentropic efficiency calculation formula of the low-pressure stage turbine is as follows:
wherein T is t-in The total temperature of the inlet of the turbine is given by the unit K; t (T) s-out The turbine outlet static temperature is given by the unit K; p (P) t-in The total pressure is the total pressure of the inlet of the turbine, and the unit Pa; p (P) s-out The unit Pa is the turbine outlet static pressure; gamma is the non-dimensional air insulation coefficient and takes the value of 1.353.
In this example, given a total high pressure stage turbine inlet temperature of 873.15K, a total high pressure stage turbine inlet pressure of 200Kpa, a low pressure stage turbine outlet static pressure of 101Kpa, and a three-dimensional numerical calculation based on Ansys-CFX was developed, wherein the high pressure stage turbine speed was 41800rpm and the low pressure stage turbine speed was 52100rpm. On the basis of this, the bypass valve is adjusted in its deflection position with respect to the interstage main pipe 1 as shown in fig. 2 (left-side bias of the bypass valve), fig. 3 (non-bias of the bypass valve), and fig. 4 (right-side bias of the bypass valve), respectively. The bypass branch 2 airflow under different bypass valve bias modes causes different distortions of the high-pressure stage outlet rotational flow, namely the inlet airflows of the low-pressure stage turbine 3 are different, and finally the isentropic efficiency of the low-pressure stage turbine calculated according to the isentropic efficiency calculation formula of the low-pressure stage turbine is shown in fig. 5, and the ordinate in fig. 5 is the isentropic efficiency of the low-pressure stage turbine. As can be seen from fig. 5, the bypass valve left bias decreases the low pressure stage turbine efficiency by about 2.5% and the bypass valve right bias increases the low pressure stage turbine efficiency by about 2.2% relative to the bypass valve unbiased condition.
The foregoing describes a specific mode of operation of the present invention. It is to be understood that the invention is not limited to the particular manner of operation described hereinabove, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without affecting the spirit of the invention.
Claims (2)
1. The design method for the eccentric intersecting of the bypass branch and the main pipe of the two-stage turbocharging system is characterized by comprising the following steps of:
the method comprises the steps that firstly, an air inlet of a high-pressure stage turbine is communicated with an engine exhaust manifold, and an air outlet of the high-pressure stage turbine is connected with an air inlet of a low-pressure stage turbine through an interstage main pipe;
step two, an air inlet of a bypass branch pipe is communicated with an engine exhaust main pipe, an air outlet of the bypass branch pipe is communicated with an interstage main pipe in front of the low-pressure stage turbine, and a bypass valve is arranged on the bypass branch pipe;
step three, respectively carrying out left-offset, unbiased and right-offset designs on the joint of the bypass branch pipe and the interstage main pipe, and respectively carrying out simulation calculation on the three designs under the condition that the bypass valve is fully opened;
and step four, respectively measuring the influence of left deviation, unbiased deviation and right deviation on the efficiency of the low-pressure stage turbine by using an isentropic efficiency calculation formula of the low-pressure stage turbine, and determining a finally adopted design scheme.
2. The method for designing the eccentric intersecting of the bypass branch and the main pipe of the two-stage turbocharging system according to claim 1, wherein the isentropic efficiency calculation formula of the low-pressure stage turbine is as follows:
wherein T is t-in The total temperature of the inlet of the turbine is given by the unit K; t (T) s-out The turbine outlet static temperature is given by the unit K; p (P) t-in The total pressure is the total pressure of the inlet of the turbine, and the unit Pa; p (P) s-out The unit Pa is the turbine outlet static pressure; gamma is the non-dimensional air insulation coefficient and takes the value of 1.353.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210943104.0A CN115292934B (en) | 2022-08-08 | 2022-08-08 | Design method for eccentric intersecting of bypass branch and main pipe of two-stage turbocharging system |
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| CN202210943104.0A CN115292934B (en) | 2022-08-08 | 2022-08-08 | Design method for eccentric intersecting of bypass branch and main pipe of two-stage turbocharging system |
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| CN115292934A CN115292934A (en) | 2022-11-04 |
| CN115292934B true CN115292934B (en) | 2024-01-26 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007154684A (en) * | 2005-12-01 | 2007-06-21 | Isuzu Motors Ltd | Two-stage supercharging type engine |
| CN103615309A (en) * | 2013-12-10 | 2014-03-05 | 吉林大学 | All-work-condition adjustable two-stage pressurizing system of internal combustion engine |
| CN105386857A (en) * | 2015-11-27 | 2016-03-09 | 吉林大学 | Internal combustion engine two-stage pressurization control system and control method thereof |
| CN108931379A (en) * | 2018-05-24 | 2018-12-04 | 北京理工大学 | A kind of turbine efficiency measurement method |
| CN113503262A (en) * | 2021-08-11 | 2021-10-15 | 北京理工大学 | Simulation method for high-low pressure turbine of two-stage supercharging system |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016157364A1 (en) * | 2015-03-30 | 2016-10-06 | 三菱重工業株式会社 | Turbine supercharger, and two-stage supercharging system |
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- 2022-08-08 CN CN202210943104.0A patent/CN115292934B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007154684A (en) * | 2005-12-01 | 2007-06-21 | Isuzu Motors Ltd | Two-stage supercharging type engine |
| CN103615309A (en) * | 2013-12-10 | 2014-03-05 | 吉林大学 | All-work-condition adjustable two-stage pressurizing system of internal combustion engine |
| CN105386857A (en) * | 2015-11-27 | 2016-03-09 | 吉林大学 | Internal combustion engine two-stage pressurization control system and control method thereof |
| CN108931379A (en) * | 2018-05-24 | 2018-12-04 | 北京理工大学 | A kind of turbine efficiency measurement method |
| CN113503262A (en) * | 2021-08-11 | 2021-10-15 | 北京理工大学 | Simulation method for high-low pressure turbine of two-stage supercharging system |
Non-Patent Citations (1)
| Title |
|---|
| 柴油机可调两级增压系统变海拔稳态调节特性研究;张来涛;徐岩;刘胜;利奇;石磊;邓康耀;杨震寰;;车用发动机(05);31-36 * |
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