A method and device for integrating a high-power marine power exhaust system
Patent Information
- Application Number
- CN202610966932.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-01
- Publication Date
- 2026-10-20
AI Technical Summary
[0003]现有技术中，各功能单元的设计方法和计算模型通常独立进行，缺乏系统性的耦合计算模型，导致一体化集成设计出现以下问题：
本发明通过依次执行设计输入确定、总体积分配估算、各功能单元性能估算以及多目标集成优化等步骤，将喷油混合、DOC、DPF、尿素混合、SCR及消音六大功能单元纳入统一的功构一体化设计流程，从而系统性地解决了各单元独立设计时无法考虑的相互耦合影响，实现了体积配额、转化效率与背压等多项相互制约性能指标的整体最优匹配，最终在有限舱室空间约束下达成多污染物一体化综合净化的效果。
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of marine power auxiliary system design technology, specifically relating to an integrated method and device for the functional structure of a high-power marine power emission system. Background Technology
[0002] With increasingly stringent ship emission standards, diesel engine exhaust aftertreatment systems for high-power marine propulsion units are becoming increasingly complex. Due to space constraints, independent unit distributed installation is virtually impossible. Therefore, traditional methods of designing individual units independently are no longer sufficient to meet the needs of integrated design. The functional units and their roles are as follows: Fuel injector: used to inject fuel during DPF active regeneration, which mixes with exhaust gas and is then oxidized and heated by DOC; DOC (Diesel Oxidation Catalyst): Oxidizes CO, HC and regenerates fuel injection, and oxidizes NO to NO2; DPF (Diesel Particulate Filter): Filters and captures particulate matter; Urea mixer: sprays urea aqueous solution, causing it to hydrolyze and produce NH3, which is then uniformly mixed with the exhaust gas; SCR (Selective Catalytic Reduction): Reduces NOx to N2; Muffler: Reduces exhaust noise.
[0003] In existing technologies, the design methods and computational models of each functional unit are usually carried out independently, lacking a systematic coupled computational model, which leads to the following problems in integrated design: Multi-parameter matching is difficult. The design parameters of each unit are coupled with each other, and independent calculations cannot take into account the mutual influence between functional units, resulting in substandard performance after integration.
[0004] Multiphysics coupling predictions are inaccurate. In finite-scale spaces, there is a lack of applicable computational models for multiphysics coupling prediction, which involve the coupling of multiple physics fields such as flow, temperature, sound, and dynamics.
[0005] Multi-objective optimization is inaccurate. The integration of various functional units involves multiple objectives such as volume, back pressure, conversion efficiency, noise reduction effect, and thermal management, and lacks a systematic design process method.
[0006] Therefore, it is urgent to construct an integrated model and method for the structure and function of high-power marine emission systems. This model and method will guide the structural parameter matching design, performance prediction, and optimization of integrated devices for high-power marine emission systems, so as to achieve the effect of integrated purification of multiple pollutants emitted by high-power marine power systems. This has significant engineering application value. Summary of the Invention
[0007] The purpose of this invention is to provide an integrated method and device for the functional structure of a high-power marine emission system, which can guide the structural parameter matching design and performance optimization of multi-unit coupling to achieve integrated purification of multiple pollutants.
[0008] To address the aforementioned technical problems, this invention provides an integrated method for a high-power marine emission system, comprising a fuel injection mixing unit, a DOC unit, a DPF unit, a urea mixing unit, an SCR unit, and a noise reduction unit; the method includes the following steps: S1. Determine the design input parameters, which include diesel engine exhaust parameters, emission control indicators, and physical characteristic constraints; S2. Based on the design input parameters, estimate the total volume allocation of each functional unit and obtain the volume quota of each functional unit; S3. Based on the volume quota, perform performance estimation on each functional unit to obtain the performance estimation results; S4. Based on the performance estimation results, perform multi-objective integrated optimization of the functional units and output the optimal design scheme that meets the constraints.
[0009] According to the above scheme, in step S2, estimating the total volume allocation of each functional unit includes: determining the required volume of each functional unit based on the exhaust volume flow rate, the residence time of each functional unit, and the carrier porosity.
[0010] According to the above scheme, in step S2, estimating the total volume allocation of each functional unit includes: allocating the axial dimension of the total length dimension based on the length of each functional unit.
[0011] According to the above scheme, in step S3, the performance estimation of each functional unit includes predicting the uniformity of oil-gas mixing and estimating the mixing length of the fuel injection mixing functional unit; wherein, the mixing length estimation is based on the shell equivalent diameter, gas density, liquid density and droplet average diameter.
[0012] According to the above scheme, in step S3, the performance estimation of each functional unit includes chemical reaction kinetic modeling, ignition characteristics and conversion efficiency estimation, and central temperature field distribution prediction for the DOC functional unit.
[0013] According to the above scheme, in step S3, the performance estimation of each functional unit includes estimating the filtration efficiency and pressure drop, evaluating the regeneration heat, and predicting the central temperature field distribution for the DPF functional unit.
[0014] According to the above scheme, in step S3, the performance estimation of each functional unit includes urea droplet breakup and evaporation analysis, urea hydrolysis reaction kinetic analysis, and ammonia distribution uniformity estimation for the urea mixing functional unit.
[0015] According to the above scheme, the performance estimation of each functional unit in step S3 includes predicting the flow uniformity, estimating the nitrogen oxide conversion efficiency, and estimating the zone temperature and reaction rate for the SCR functional unit; and estimating the sound transmission loss, pressure loss, and carrier-assisted sound silencing contribution for the silencing functional unit.
[0016] According to the above scheme, in step S4, the multi-objective integrated optimization of the execution function unit includes: establishing objective functions and constraints for integrated volume, back pressure, conversion efficiency, noise reduction effect and thermal management, performing parameter sensitivity analysis, and determining the optimal design scheme.
[0017] This invention also provides an integrated device for a high-power marine emission system, wherein the high-power marine emission system includes a fuel injection mixing unit, a DOC unit, a DPF unit, a urea mixing unit, an SCR unit, and a noise reduction unit; the device includes: The volume allocation module is used to estimate the total volume allocation of each functional unit based on the design input parameters and obtain the volume quota of each functional unit. Multiple functional unit estimation modules are used to perform performance estimation on each functional unit based on the volume quota and obtain performance estimation results; the multiple functional unit estimation modules include a fuel injection and mixing functional unit estimation module, a DOC functional unit estimation module, a DPF functional unit estimation module, a urea mixing functional unit estimation module, an SCR functional unit estimation module, and a noise reduction functional unit estimation module. The multi-objective integrated balancing module is used to perform multi-objective integrated optimization of functional units based on the performance estimation results, and output the optimal design scheme that meets the constraints.
[0018] Beneficial effects This invention integrates six major functional units—fuel injection mixing, DOC, DPF, urea mixing, SCR, and silencing—into a unified functional structure design process by sequentially executing steps such as design input determination, overall volume allocation estimation, performance estimation of each functional unit, and multi-objective integrated optimization. This systematically solves the mutual coupling effects that cannot be considered when each unit is designed independently, and achieves the overall optimal matching of multiple mutually restrictive performance indicators such as volume quota, conversion efficiency, and back pressure. Ultimately, it achieves the effect of integrated purification of multiple pollutants under the constraint of limited cabin space. Attached Figure Description
[0019] Figure 1This is an integrated flowchart of a high-power marine emission system according to an embodiment of the present invention. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.
[0021] (I) Model and Method like Figure 1 As shown, an integrated process method for a high-power marine emission system is presented. This invention provides an integrated process method for a high-power marine emission system, characterized in that the high-power marine emission system includes a fuel injection mixing unit, a DOC unit, a DPF unit, a urea mixing unit, an SCR unit, and a noise reduction unit; the method includes the following steps: S1. Determine the design input parameters, which include diesel engine exhaust parameters, emission control indicators, and physical characteristic constraints; S2. Based on the design input parameters, estimate the total volume allocation of each functional unit and obtain the volume quota of each functional unit; S3. Based on the volume quota, perform performance estimation on each functional unit to obtain the performance estimation results; S4. Based on the performance estimation results, perform multi-objective integrated optimization of the functional units and output the optimal design scheme that meets the constraints.
[0022] The following is combined with Figure 1 The method is divided into nine design phases, with each step described in detail.
[0023] S1. Design Input Determination Phase The first stage is determining the design inputs. This step involves defining three basic input parameters that provide the design boundaries for the entire process: 1. Diesel engine exhaust parameters; 2. Emission control targets; 3. Physical characteristic constraints. This stage marks the beginning of the entire design process. Once these three types of input conditions are defined, step S1 is complete, and the result is output to the next stage.
[0024] S2, Total Volume Distribution Estimation Stage The second stage is the estimation of the total volume allocation. Based on the upstream input conditions, this step plans the overall volume of the post-processing system. This involves both allocating volume quotas to each functional unit and establishing a quantitative model for volume allocation. Specifically, step S2, estimating the total volume allocation of each functional unit, includes: (1) Volume Requirement Estimation Model: The volume required by each functional unit is determined by reaction kinetics. Based on the exhaust volume flow rate, residence time of each functional unit, and carrier porosity, the required volume of each functional unit is determined. The model formula is:
[0025] in, The volume (m) required for the i-th functional unit 3 ); exhaust volume flow rate (m³) 3 / s); The dwell time (s) of the i-th functional unit; The porosity is the carrier porosity.
[0026] (2) Axial dimension allocation model: The axial dimension of the total length is allocated according to the length of each functional unit. The formula for estimating the total length dimension is:
[0027] in, Total length (m); Length of the fuel injection mixing unit (m); The length of the DPF functional unit (m); The length of the DOC functional unit (m); Length of the urea mixing functional unit (m); The length of the SCR functional unit (m); The length (m) of the noise reduction unit.
[0028] Using the two models above, estimate the total volume allocation of each functional unit, obtain the volume quota of each functional unit, and complete step S2.
[0029] S3. Performance estimation stage for each functional unit: Based on the volume quota, the performance of each functional unit is estimated to obtain the performance estimation results. This step includes stages 3 to 8, corresponding to the estimation of six functional units: fuel injection mixing, DOC, DPF, urea mixing, SCR, and muffler.
[0030] Phase 3: Fuel Injection Mixing Unit Estimation. This step corresponds to step S3, which involves predicting the uniformity of fuel-air mixing and estimating the mixing length of the fuel injection mixing unit. It is further broken down into two tasks: 1. Predicting the uniformity of fuel-air mixing; 2. Estimating the mixing length. This step specifically estimates the fuel injection mixing unit at the post-treatment front end, evaluating the uniformity of fuel-air mixing and the mixing section length required to achieve the target uniformity. The characteristic length estimation model for the fuel injection mixing zone (based on the shell equivalent diameter, gas density, liquid density, and average droplet diameter) is as follows:
[0031] in, This is an empirical coefficient, typically ranging from 0.8 to 1.2. Density of gases and liquids (kg / m³) 3 ); The equivalent diameter of the shell (m); The average diameter of the droplet (m); This is the mixing coefficient, which is generally taken as 0.4 to 0.8.
[0032] Phase 4: DOC Functional Unit Estimation. This step corresponds to step S3, which involves chemical reaction kinetic modeling, ignition characteristics and conversion efficiency estimation, and core temperature field distribution prediction for the DOC functional unit. It is further broken down into three tasks: 1. Chemical reaction kinetic modeling; 2. Ignition characteristics and conversion efficiency estimation; 3. Core temperature field distribution prediction. Specific estimation models include: 1) DOC conversion efficiency estimation model:
[0033] As an activating reaction factor; The ratio of surface area to volume (m²) 2 / m 3 L is the length of the carrier (m); The velocity is denoted as m / s.
[0034] 2) DOC outlet temperature estimation model (used to calculate DOC temperature rise during active fuel injection regeneration): During active fuel injection regeneration, DOC temperature rise:
[0035] in, The regeneration injection flow rate is (kg / s). It has the lowest calorific value (J / kg) for diesel fuel. For oxidation efficiency; The flue gas flow rate is (kg / s). Specific heat of flue gas (J / kg.K).
[0036] This step corresponds to step S3, which involves estimating the filtration efficiency and pressure drop, assessing the regeneration heat, and predicting the center temperature field distribution for the DPF functional unit. It is further broken down into three tasks: 1. Estimating filtration efficiency and pressure drop; 2. Estimating the regeneration heat; 3. Predicting the center temperature field distribution. Specific estimation models include:
[0037] in, The surface area per unit volume of the carrier (m²) 2 / m 3 ); The diameter of the particle (m); Porosity of the carrier; is the capture coefficient.
[0038] 2) DPF pressure drop estimation model:
[0039] in, This is the local drag coefficient; The coefficient of friction; The channel length is in meters (m). Hydraulic diameter (m); The exhaust dynamic viscosity (Pa.s) Wall thickness (m); Wall permeability (m 2 ).
[0040] Phase 6: Estimation of Urea Mixed Functional Units This step corresponds to step S3, which involves analyzing urea droplet breakup and evaporation, performing urea hydrolysis reaction kinetics, and estimating ammonia distribution uniformity within the urea mixing functional unit. It is further broken down into three tasks: 1. Modeling urea droplet breakup and evaporation; 2. Modeling urea hydrolysis reaction kinetics; 3. Estimating ammonia distribution uniformity. Specific estimation models include: 1) Urea mixture characteristic length estimation model:
[0041] in, For safety margin, a value of 1.5 to 2 is generally used; The characteristic time (s) for urea hydrolysis; The urea flow rate is (m / s).
[0042] 2) Ammonia distribution uniformity estimation model:
[0043] in: ammonia standard concentration (mol / m³) 3 ); The average concentration of ammonia (mol / m³) 3 ).
[0044] Phase 7: SCR Functional Unit Estimation This step corresponds to step S3, which involves predicting the flow uniformity of the SCR functional unit, estimating the nitrogen oxide conversion efficiency, and estimating the zoned temperature and reaction rate. The SCR functional unit estimation is further broken down into three tasks: 1. Flow uniformity prediction; 2. Nitrogen oxide conversion efficiency estimation; 3. Zoned temperature and reaction rate estimation. Specific estimation models include: 1) SCR conversion efficiency estimation model:
[0045] in, exhaust volume flow rate (m³) 3 / h); SCR carrier volume (m 3 ); The characteristic space velocity (1 / h) depends on the catalyst formulation; For maximum conversion efficiency, it depends on the catalyst formulation.
[0046] 2) Estimation model for the noise reduction functional unit: Estimation of acoustic transmission loss in the expansion cavity:
[0047] in, Expansion ratio; Wave number (rad / m); The length of the chamber is (m).
[0048] Phase 8: Estimation of the Silencing Functional Unit This step corresponds to step S3, which involves estimating the sound transmission loss, pressure loss, and carrier-assisted noise reduction contribution of the noise reduction functional unit. The noise reduction functional unit estimation is further decomposed into three tasks: 1. Sound transmission loss estimation; 2. Pressure loss estimation; 3. Carrier-assisted noise reduction contribution model.
[0049] Estimation of acoustic transmission loss in perforated tubes:
[0050] in, Perforation rate; is the impedance of the perforation, and c is the speed of sound.
[0051] S4. Functional Unit Multi-Objective Integration Optimization Stage The ninth stage is the multi-objective integrated optimization of functional units. Based on the performance estimation results, this step performs multi-objective integrated optimization of functional units and outputs the optimal design scheme that satisfies the constraints. It is broken down into three tasks: 1. Establishing the objective function and constraints; 2. Parameter sensitivity analysis; 3. Determining the optimal design scheme. This stage integrates the parameters and performance indicators of all the aforementioned functional units, constructs a multi-objective optimization system, identifies key influencing factors through parameter sensitivity analysis, and finally determines the globally optimal post-processing system design scheme.
[0052] In step S4, the multi-objective integrated optimization of the execution functional unit includes: establishing objective functions and constraints for integrated volume, back pressure, conversion efficiency, noise reduction effect, and thermal management; performing parameter sensitivity analysis; and determining the optimal design scheme. The multi-objective integrated equilibrium model is as follows:
[0053] in, These are the weighting coefficients. For maximum pressure drop, For the conversion efficiency of SCR, DOC, and DPF, The conversion efficiency of the integrated device is given by TL, where TL represents the acoustic transmission loss. The acoustic transmission loss of the integrated device is represented by V, where V is the volume of the carrier. The volume of the integrated device carrier.
[0054] This embodiment also provides an integrated device for a high-power marine emission system, wherein the high-power marine emission system includes a fuel injection mixing unit, a DOC unit, a DPF unit, a urea mixing unit, an SCR unit, and a noise reduction unit; the device includes: The volume allocation module is used to estimate the total volume allocation of each functional unit based on the design input parameters and obtain the volume quota of each functional unit. Multiple functional unit estimation modules are used to perform performance estimation on each functional unit based on the volume quota and obtain performance estimation results; the multiple functional unit estimation modules include a fuel injection and mixing functional unit estimation module, a DOC functional unit estimation module, a DPF functional unit estimation module, a urea mixing functional unit estimation module, an SCR functional unit estimation module, and a noise reduction functional unit estimation module. The multi-objective integrated balancing module is used to perform multi-objective integrated optimization of functional units based on the performance estimation results, and output the optimal design scheme that satisfies the constraints. The specific implementation methods and internal models of each module have been described in detail in the above method flow, and will not be repeated here.
[0055] Taking a certain ship diesel generator set as an example, the design input parameters are: exhaust flow rate: 0.15 kg / s, DOC inlet temperature: not lower than 250℃, volume constraints: length less than 700 mm, outer diameter less than 350 mm.
[0056] The estimation results are as follows:
[0057] Theoretical estimation has preliminarily verified that the estimation model and method are basically feasible and can be used to guide the design of actual ship emission systems.
[0058] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.
[0059] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for integrating the functional structure of a high-power marine emission system, characterized in that, The ship's high-power emission system includes a fuel injection mixing unit, a DOC unit, a DPF unit, a urea mixing unit, an SCR unit, and a noise reduction unit; the method includes the following steps: S1. Determine the design input parameters, which include diesel engine exhaust parameters, emission control indicators, and physical characteristic constraints; S2. Based on the design input parameters, estimate the total volume allocation of each functional unit and obtain the volume quota of each functional unit; S3. Based on the volume quota, perform performance estimation on each functional unit to obtain the performance estimation results; S4. Based on the performance estimation results, perform multi-objective integrated optimization of the functional units and output the optimal design scheme that meets the constraints.
2. The integrated method for the functional structure of a high-power marine power emission system according to claim 1, characterized in that, In step S2, estimating the total volume allocation of each functional unit includes: determining the required volume of each functional unit based on the exhaust volume flow rate, the residence time of each functional unit, and the carrier porosity.
3. The integrated method for the functional structure of a high-power marine power emission system according to claim 1 or 2, characterized in that, In step S2, estimating the total volume allocation of each functional unit includes: allocating the axial dimension of the total length based on the length of each functional unit.
4. The integrated method for the functional structure of a high-power marine power emission system according to claim 1, characterized in that, In step S3, the performance estimation of each functional unit includes predicting the uniformity of oil-gas mixing and estimating the mixing length for the fuel injection mixing functional unit; wherein, the mixing length estimation is based on the shell equivalent diameter, gas density, liquid density and droplet average diameter.
5. The integrated method for the functional structure of a high-power marine power emission system according to claim 1, characterized in that, In step S3, the performance estimation of each functional unit is performed, including chemical reaction kinetic modeling, ignition characteristics and conversion efficiency estimation, and central temperature field distribution prediction for the DOC functional unit.
6. The integrated method for the functional structure of a high-power marine power emission system according to claim 1, characterized in that, In step S3, the performance estimation of each functional unit includes estimating the filtration efficiency and pressure drop, the regeneration heat assessment, and the center temperature field distribution for the DPF functional unit.
7. The integrated method for the functional structure of a high-power marine power emission system according to claim 1, characterized in that, In step S3, the performance estimation of each functional unit includes urea droplet breakup and evaporation analysis, urea hydrolysis reaction kinetic analysis, and ammonia distribution uniformity estimation for the urea mixing functional unit.
8. The integrated method for the functional structure of a high-power marine power emission system according to claim 1, characterized in that, The performance estimation of each functional unit described in step S3 includes predicting the flow uniformity, estimating the nitrogen oxide conversion efficiency, and estimating the zone temperature and reaction rate for the SCR functional unit; and estimating the sound transmission loss, pressure loss, and carrier-assisted sound attenuation contribution for the silencing functional unit.
9. The integrated method for the functional structure of a high-power marine power emission system according to claim 1, characterized in that, In step S4, the multi-objective integrated optimization of the execution function unit includes: establishing objective functions and constraints for integrated volume, back pressure, conversion efficiency, noise reduction effect and thermal management, performing parameter sensitivity analysis, and determining the optimal design scheme.
10. An integrated device for a high-power marine emission system, characterized in that, The ship's high-power emission system includes a fuel injection mixing unit, a DOC unit, a DPF unit, a urea mixing unit, an SCR unit, and a noise reduction unit; the device includes: The volume allocation module is used to estimate the total volume allocation of each functional unit based on the design input parameters and obtain the volume quota of each functional unit. Multiple functional unit estimation modules are used to perform performance estimation on each functional unit based on the volume quota and obtain performance estimation results; the multiple functional unit estimation modules include a fuel injection and mixing functional unit estimation module, a DOC functional unit estimation module, a DPF functional unit estimation module, a urea mixing functional unit estimation module, an SCR functional unit estimation module, and a noise reduction functional unit estimation module. The multi-objective integrated balancing module is used to perform multi-objective integrated optimization of functional units based on the performance estimation results, and output the optimal design scheme that meets the constraints.