Two-dimensional piston pump: Principle, design,and testing for aviation fuel pumps

Aviation fuel pumps of the future are required to be highly efficient and lightweight.As such,this work presents the designs of various mechanisms and structures of advanced twodimensional piston pumps for aero-engines,and their universal kinematic design methods are detailed herein.The efficiency of various piston pump prototypes was experimentally tested at various speeds in an open circuit.The experimental results indicate that two-dimensional piston pumps have a volumetric efficiency>91%and a higher power–mass ratio than conventional fuel pumps under all the conditions studied.Furthermore,the structural and material problems encountered during testing can provide a blueprint for further improvement of the design and processing of two-dimensional piston fuel pumps.

T01067∗Series Fuel Pump Pulp Molded Package Dynamic Drop Simulation

In this paper,combined with the actual situation encountered in the process of product transportation,the finite element analysis software ANSYS/LS-DYNA was used to simulate the dynamic drop process of the buffer packaging structure of T01067∗series fuel pump,and the simulation results were analyzed,and a conclusion was drawn.According to the fuel pump weight calculation buffer material thickness,according to the product size and structure design of the pulp molded cushion structure,simulation of static cushioning performance,and dynamic drop simulation,for the subsequent structural optimization cost reduction to provide early warning[1,2].Check the simulation production cost,reducemany times a large number of experiments and time,structure is ideal type prediction,find out the ideal optimization total,physical test,further optimization and improvement[3].

CONSTRUCTION METHOD OF KNOWLEDGE MAP BASED ON DESIGN PROCESS

Due to the increasing amount and complexity of knowledge in product design, the know-ledge map based on design process is presented as a tool to reuse product design process, promote the product design knowledge sharing. The relationship between design task flow and knowledge flow is discussed; A knowledge organizing method based on design task decomposition and a visualization method to support the knowledge retrieving and sharing in product design are proposed. And a knowledge map system to manage the knowledge in product design process is built with Visual C＋＋ and SVG. Finally, a brief case study is provided to illustrate the construction and application of knowledge map in fuel pump design.

Numerical simulation research on multiphase flow of aviation centrifugal pump based on OpenFOAM

This paper aims to tackle the calculation efficiency problem raised in the cavitation-flow simulation of the aviation centrifugal pump due to the fading-away interface resulting from the dissipation of numerics used in the phase-change control equation for unstructured-grid multiphase flow,and due to the limitation of flow time-step in whole flow regimes,the control equation of vapor–liquid two-phase flow considering cavitation mass transport is established firstly,modifying the momentum equation by introducing the surface tension,and adding the artificial convective flow to the phase equation to solve the numerical dissipation problem.Secondly,in consideration of the local time step principle and based on the multi-dimensional general limiter algorithm with explicit solutions under the OpenFOAM platform,a solution method of steady-state VOF (Volume of Fluid) model considering cavitation two-phase change is constructed,and the feasibility of this method is verified by NACA hydrofoil and NASA flat plate inducer.Finally,based on the platform developed,the cavitation performance of an aviation centrifugal pump inducer is analyzed.The research results show that the error of the calculated cavitation pressure distribution for NACA hydrofoil between the simulation test and the experimental-test is less than 5%,and the maximum error of calculated cavitation number at pump head dropping for NASA high-speed flat plate inducer between the simulation test and the experimental-test is 2.1%.The cavitation area observed in the simulation test is the same as that obtained in the high-speed photography test.Based on the OpenFOAM simulation method,the position of pump head dropping of the fuel centrifugal pump can be accurately captured.The error of the calculated cavitation number at pump head dropping between the simulation test and the experimental test is about 3.7%,showing high calculation accuracy.

Remaining useful life prediction based on variation coefficient consistency test of a Wiener process

High-cost equipment is often reused after maintenance, and whether the information before the maintenance can be used for the Remaining Useful Life （RUL） prediction after the maintenance is directly determined by the consistency of the degradation pattern before and after the maintenance. Aiming at this problem, an RUL prediction method based on the consistency test of a Wiener process is proposed. Firstly, the parameters of the Wiener process estimated by Maximum Likelihood Estimation （MLE） are proved to be biased, and a modified unbiased estimation method is proposed and verified by derivation and simulations. Then, the h statistic is constructed according to the reciprocal of the variation coefficient of the Wiener process, and the sampling distribution is derived. Meanwhile, a universal method for the consistency test is proposed based on the sampling distribution theorem, which is verified by simulation data and classical crack degradation data. Finally, based on the consistency test of the degradation model, a weighted fusion RUL prediction method is presented for the fuel pump of an airplane, and the validity of the presented method is verified by accurate computation results of real data, which provides a theoretical and practical guidance for engineers to predict the RUL of equipment after maintenance.