HMB Optimal Design Based On Fluid Characteristic Simulation Of Pipeline Networks

It is universal requirement for the typical hydraulic system realizing integrity andstandardrization to develop the integrated disposition of hydraulic valves. As the carrier of allkinds of valves, hydraulic manifold block (HMB) is one of the key parts of integratedhydraulic system. According to a general survey of foreign and domestic circumstance ofstudy at present, HMB design mainly focus on the structure design for the angle of valveslayout at outer and holes arrangement at inner of hexahedron. With the development ofindustrial technology, the demand for performance of system is increasing. As far as HMB isconcerned, this is composed by complex pipeline networks, and the inner flow status inconnective pipeline networks affect the energy loss and movement characteristic of the wholesystem directly. For this situation, the paper studied the flow mechanism in HMB, discussedthe influence factors of the structure parameters to the flow characteristic, then improved thestructure design of HMB, which make the design result of HMB not only satisfy therequirement of connection and installation, but also realize the performance matching, so as toachieve the aim of optimal design of HMB on higher quality base. Computational fluiddynamic (CFD) method is applied in this paper to simulate the flow characteristic in pipelinenetworks of HMB, the main study contents and results are as follows:According to the structure feature of pipeline networks and executing functions ofexternal parts, 3D coupling mathematical models which fit static and dynamic analysis offlow in HMB at cylindrical coordinate, was proposed. The flow in pipeline networks of HMBcan be classified as steady and unsteady flow. The transient state equations of Navier-Stokesin turbulence flow of steady one was treated with time average method in the models, and lowRe number k-εequations about turbulence energy k and dissipationsεwere introduced. Inunsteady flow, the time-dependence motion equations were loaded to the coupling models,with considering the flow viscosity. The models provide a mathematical foundation for theflow field simulation. Then the coupling models were discretized with the finite volumemethod (FVM) and solved with SIMPLE algorithm.Based on the project data base of previous work, 3D solid structure (that is flow region)of pipeline networks was generated with object oriented method, then, the solid structure wasdiscretized by block-structured gird based on body-fitted coordinate. The models solution quality was improved by adding density in the key solved region. The building of structuresolid and grid automatic generation provide guarantee to solve above-mentionedmathematical models and build pipeline network simulation platform.With analyzing of the execution function of outer parts in HMB and complexcharacteristic of the pipeline ports, the solving rules of boundary are given, and the strategy ofports distinguishing and boundary setting are proposed, which is from rule-based heuristicsalgorithm. The result indicated that, according to the searching direction of the regulation sets,the boundary condition group can be found, which can guarantee the single boundarycondition of port, satisfy oil flow order, and comform to execution function of outer parts.Above research content provided technical support for CFD simulation of HMB pipelinenetworks. In this paper, the CFD method was applied to simulate the typical flow channel ofHMB in the quarter turn, Z type, T type, craft channel and so on. The relations of typical flowchannels characteristic (such as velocity, flow streamlines, flow separation andre-convergence, swirl generation and disappearance) and energy losses was analyzedqualitatively, and the function relations of typical channel flow resistance and structureparameters was given quantitatively. On the basis of comprehensive summary of influencerule of typical structure in HMB pipeline networks to flow characteristics, the expressionformula of characteristic variable related with structure design was defined by the method ofobject oriented. Moreover, the evaluation objective and adjustment rules for second designaccording to the performace were confirmed. Finally, HMB overall optimization design,where the structural design and the performance design were merged into one system, wasrealized.With comprehensively thoroughly understanding the HMB pipeline networks simulationprocess as well as flow characteristic, secondary development of CFD software Fluent usingVisual C++ platform was carried on, and HMB optimal design based on fluid characteristicsimulation of pipeline networks automatically was successfully realized. This system mainlyconsisted of project data module, boundary condition module, grid production module andappraisal rule module. Through inserting this design system to the structural design system ofearlier period development by project group which optimizes based on the intelligence, theHMB automatic optimization design platform that can realize structure optimization andperformance optimization was developed with great efficiency. Finally, an example was givento testify the system effectiveness and method feasibility of this paper.