基于功能流的产品族概念设计过程研究

通过分析产品族设计过程存在的不足,结合产品设计过程的特性,提出了产品族设计过程中功能流的概念,并建立了基于功能流的产品族设计集成框架。该框架将需求获取、概念设计过程和详细设计过程以功能流为纽带统一起来。重点阐述了概念设计阶段用户需求功能的获取和设计功能之间的转化及功能结构模型的建立。最后以多功能台式机器人概念设计过程为实例验证了上述理论的可行性。     

面向类比思维的创新问题求解过程

为促进设计者在创新问题求解过程中产生创新概念,从类比思维的认知过程出发,提出从功能、行为、结构三个角度所对应的抽象层次及语义层次来描述相似特征,构建以相似特征为基础的创新问题求解模型,用于实现问题空间和知识空间不断映射求解,激励设计者形成创新概念。该模型主要包括问题表征、设计检索及映射迁移三个求解步骤。首先,以相似特征为基础,从功能、行为及结构的不同抽象层次表征设计问题,并基于抽象层次和语义层次知识检索,实现类比源的获取,完成知识的映射迁移。最后基于课题组开发的产品创新设计服务平台的创新问题求解模块,以波轮式洗衣机的创新问题求解示例说明该模型的应用。     

基于知识流的产品创意知识获取方法

为全面获取工业设计过程中的创意知识,提出一种将设计阶段与知识流节点匹配进行知识管理的方法。通过比较创意知识与工程领域设计知识之间的差异,探讨了工业设计领域的创意知识特殊范畴,将其知识空间划分为静态和动态两种,并进行创意知识建模。根据新产品开发成员协同创新的过程,提出了新产品开发过程多粒度模型,据此建立了创意知识流,将设计阶段与知识节点匹配。基于节点知识本体来识别创意知识源,通过分裂、合并、派生、插入、修剪等节点操作,以及标示节点之间的条件、排斥和协同关系,对设计案例的动态信息进行捕捉和转化。以灯具新产品开发中的创意知识获取为例,验证了该方法的有效性。     

基于功能流的产品族概念设计过程研究

通过分析产品族设计过程存在的不足,结合产品设计过程的特性,提出了产品族设计过程中功能流的概念,并建立了基于功能流的产品族设计集成框架.该框架将需求获取、概念设计过程和详细设计过程以功能流为纽带统一起来.重点阐述了概念设计阶段用户需求功能的获取和设计功能之间的转化及功能结构模型的建立.最后以多功能台式机器人概念设计过程为实例验证了上述理论的可行性.     

斜流泵研究进展

由于斜流泵兼有离心泵和轴流泵的优点,其应用范围越来越广.首先根据比转速的不同对斜流泵进行了分类,介绍了斜流泵的结构特点、能量特性以及存在的问题.对现有的斜流泵的设计方法即传统设计法、逆向求解设计法以及控制速度矩设计法的优势及不足进行了总结.在斜流泵的设计中需要注意的细节包括轮缘间隙、叶片角变化、绘型技术以及轴面图设计等.轴面图设计是影响斜流泵性能的一个重要因素,通过合理的改进轴面图形状,可以提高设计点效率、改善小流量点的驼峰.应用PIV测试以及CFD技术可以获取并分析斜流泵的内部流动特性.     

基于功能流的复杂产品模块划分方法研究

为更好实现复杂产品的模块化设计,在基于功能-结构的概念模型中引入模块划分技术,结合复杂产品设计的特点,提出了一种基于功能流的复杂产品模块划分模型;通过功能流将需求分析、功能分解、功能实现和模块划分统一起来.分析了复杂产品概念设计的功能分解和设计功能之间的联系和转化及功能模块划分.并结合汽轮机设计的应用实例,验证了该方法的有效性.     

复杂机电系统多流问题分析与求解过程模型

复杂机电系统在物质流、能量流和信息流的相互传递和转换过程中,流的属性及类型变化会对其他流产生负作用,造成系统产生多种流问题。针对此类问题提出流阈概念,并以此将多流问题进行分类,建立了多流问题分析的流结构信息(MFP-FSI)模型,该模型以图表形式直观展现多流问题,可从本质上揭示流问题产生机理。文中给出了流进化法则与多流问题求解的对应关系,建立了复杂机电系统多流问题分析与求解的总过程模型,最后以线香捆扎机为例验证了过程模型的可行性。     

概念设计中的F-B-S-E模型和作用流方法

在机械运动系统概念设计中 ,引入工作环境的概念 ,给出了功能—行为—结构—工作环境的功能设计信息模型 ,通过输入输出作用流表达运动行为。与目前普遍使用的输入输出对象方法 (“三流”———物料、能量和信息流 )相比 ,此方法不仅更适合于概念设计 ,而且具有重要意义。基于以上策略 ,通过分析设计、工作环境、设计的部件、属性及其属性表达以及约束等等之间相关的“作用流”来研究功能设计信息     

基于漂移流模型的管道一维气液两相流数值仿真与分析

两相流模型受到双曲线性质的影响，因为很难获得雅可比矩阵的简洁解析表达式，从而限制了开发Roe型黎曼求解器。针对管道气液两相流流动现象，利用一维气液两相流漂移流模型，建立了管道一维气液两相流控制方程，采用基于时间的限制器，使用Lax-Wendroff方法求解方程组，并以此开发了数值求解器。以垂直管中油气两相流为模型算例，计算了不同时刻的管中沿管道方向的含气率分布，通过分析比较，文中采用的漂移流一维气液两相流模型和数值算法能够满足管道一维气液两相流流动的工程应用。     

一类可持续性功能创新过程研究及软件开发

为确保资源的可持续利用和良好的生态环境,从前端预防的理念出发构建可持续性功能创新过程模型,包括可持续性设计需求的获取、功能组合与优化、功能失效判定与消除、功能求解、可持续性评价等.基于所建立的可持续性功能创新过程模型进行了软件系统开发,并探索性地应用于太阳能电池生产线关键装置的创新设计,以验证方法与软件的可行性.     

Salinity and flow regime independent multiphase flow measurements

For oil production fields, there is a need for downhole measurements of the gas/water/oil multiphase flow. In extreme conditions a relatively simple, robust, and non-intrusive system will be appropriate. A measurement setup that combines multiple gamma beam (MGB) and dual modality densitometry (DMD) measurements, would be able to determine the gas volume fraction (GVF) independently of the flow pattern, and monitor changes in water salinity. MGB measurements of gamma-ray transmission along multiple sections across the oil pipe will provide information on the flow pattern. Whereas the DMD principle will give information on changes in salinity from a combination of transmission and scattering gamma-radiation measurements. In this work we present the results from MGB and DMD measurements of a multiphase flow with high-speed gamma-ray tomograph measurements as reference for the flow pattern. The MGB measurements should enable us to distinguish between stratified or wavy/slug and annular or slug flow. Flow patterns with several minor components distributed evenly over the measurement cross section, like bubble flow, will be interpreted as homogeneous flow. The DMD measurements can be used to monitor salinity changes of the water component for intervals where the GVF is low and the water cut of the liquid is high. Combined with other gauges for water cut measurements, the MGB and DMD measurement setup should improve the multiphase flow measurements, and enable increased oil/gas recovery and production water monitoring.     

Work flow control in the flexible flow line

This research involves the development and evaluation of a part flow control model for a type of flexible manufacturing system (FMS) called a dedicated flexible flow line (FFL). In the FFL, all part types flow along the same path between successive machine groups. The specific objective of the part flow control model for the FFL is to minimize makespan for a given set of parts produced in a FFL near-term schedule, given fixed available buffer constraints. The control model developed in this research involved the repeated, real-time execution of a mathematical programming algorithm. The algorithm attempts to release the right mix of parts at the tight time to keep the FFL operating smoothly. The focus of the approach is directed toward managing WIP buffers for each machine group queue. The algorithm specifically incorporates stochastic disturbance factors such as machine failures. Through a limited number of simulation experiments, performance of the control model is shown to be superior to other parts releasing and control methods reported in the literature.     

阻塞流工况调节阀流量系数计算

简要介绍了阻塞流工况的判别及其流量系数Kv值的计算。     

A viscous flow calculation of the stern flow

Two computer codes have been developed to solve the Reynolds averaged Navier-Stokes equations; namely the fully elliptic method and the partially parabolic method. These are applied to simulate flows over the stern of the SSPA model as a bench mark, and also a multi-purpose ship with a barge type stern. The numerically generated body-fitted coordinate system is used to manage the complex geometry of the ship hull. A standard form of thek-ε turbulence model is adopted for modelling of the Reynolds stresses. Simulated results by both methods are nearly identical and the partially parabolic method can save about a half of the memory storage and 20% of CPU time in comparison with the fully elliptic method. The capability of programs is confirmed by successfully simulating pressures, skin frictions and mean velocities over sterns of the two models. Simulated nominal wake fractions show good accordance with wake measurements and the viscous resistance is accurate enough for the hull form design.     

T型管流场混合多相流与欧拉多相流模型的数值研究

以计算流体动力学(CFD)的多相流数值计算理论及方法为基础,对处于复杂工况的T型管连接装置腔内流场进行了数值模拟分析,采用标准湍流模型和标准壁面函数对T型管接头内部流场进行了数值模拟;同时以混合模型求得的解作为用欧拉多相流模型的初始条件,采用欧拉多相湍流模型进行了对T型管接头内部流场数值计算.最后对两种模型计算得到的T型管接头内部流场的压力场、速度场及气相的体积分数(VOF)分布进行了对比分析.计算结果将指导的结构优化设计及失效分析.     

非均匀来流对涡轮流场的影响

涡轮机械的非均匀进口来流会使得涡轮的流场不均匀,从而影响涡轮的工作性能。本文根据涡轮的工作机理,建立了存在叶尖间隙的涡轮流动模型,考虑来流的周向非均匀性,研究了涡轮流场的变化规律,讨论了不同来流参数对涡轮流场参数的影响。     

The fractal flow conditioner for orifice plate flow meters

The sensitivity of orifice plate flow meters to the quality of the approaching flow continues to be a cause for concern in flow metering. The distortions caused by pipe fittings such as valves, bends, compressors and other devices located upstream of the orifice plate can lead to non-standard velocity profiles and give errors in measurement. The design of orifice plate meters that are independent of the initial flow conditions of the upstream is a major goal in flow metering. Either using a long straight pipe, or a flow conditioner upstream of an orifice plate, usually achieves this goal.The effect of a fractal flow conditioner for both standard and non-standard flow conditions was obtained in experimental work and also using simulations. The measurement of mass flow rate under different conditions and different Reynolds numbers was used to establish a change in discharge coefficient relative to a standard one. The experimental results using the fractal flow conditioner show that the combination of an orifice plate and a fractal flow conditioner is broadly insensitive to upstream disturbances.The simulation results also show that the device can be used as a part of a flow metering package that will considerably reduce installation lengths. Previous work with orifice plates has shown that a combination of flow conditioner and orifice plate was promising. The results of using a combination of the fractal flow conditioner and orifice plate for non-standard flow conditions including swirling flow and asymmetric flow show that this package can preserve the accuracy of metering up to the level required in the Standards.     

两相流流动测试技术方法综述

两相流体的流动工况在动力、化工、核能、制冷、石油、冶金等工业中经常遇到。主要对流动的测试方法做了简单的总结，包括以两相流的流量、空泡率、流型、气泡各方面为测试对象的技术方法。     

Development of a flow control valve with digital flow compensator

Flow control valves typically use mechanical pressure drop compensator or dynamic flow meter to lessen the impact of pressure drop on outlet flow. However, there are some disadvantages, such as complex mechanical structure and small flow capacity. In this paper, a kind of digital flow compensator with bilinear interpolation algorithm is presented to compensate the pressure drop, in which the pressure drop and the desired outlet flow are the two input parameters. A two-stage proportional flow control valve with the proposed compensator is investigated. Pressure drop across the metering orifice of the valve is measured and fed back to the proposed compensator. If the detected pressure drop has deviated from the threshold, then the compensator will generate a compensation signal to adjust the poppet opening of the valve, which ensures that the output flow is independent of the pressure drop. Performances of the valve with the proposed compensator are investigated by simulation and experiment. Results show that it has a reasonable static control characteristics. In addition, there is no dead-zone in its steady flow curve; pressure drop have little impact on its output flow. Its dynamics will be affected by pressure drop and input voltage. Increasing pressure drop can improve system dynamics under constant input signal conditions. On the other hand, increasing input signal can shorten the poppet's closing time, but it will result in the longer opening time and the greater overshoot in the opening stage.