Starting system plays an important role in a hydraulic free piston engine (HFPE) and hydraulic accumulator/directional control valve combination is often employed. In this paper, the starting process of a typical starting system composed of a hydraulic bladder accumulator is firstly described, and then the mathematical model of the starting system is established and analyzed as well as some special situations are discussed.

Based on introduction of the basic configuration, working features of hydraulic drive system of the cutter head in a shield machine, the internal structure of the bidirectional variable displacement pump, BVDP, as the kernel element in the above hydraulic system, is depicted and compared with the ordinary variable plunger pump. Then the working principle and process of hydraulic pilot operated servo displacement adjustment about the BVDP are discussed in detail, and then the mathematical models and its transfer functions of the positive and negative displacement adjustments are established respectively. Also, the relationships between the primary performance indices such as stability condition, positioning stiffness, steady-state error, as well as initial control pressure and system parameters are analysis and concluded.

Bipropellant-powered hydraulic free piston engine (BHFPE), as a new type of HFPE, takes advantage of bipropellant in place of conventional fossil fuel, and adopts a catalytic ignition instead of the conventional spark or compression ignition. In this paper, the operational principle and working process of a BHFPE are described firstly, then the chemical formula and molar mass as well as the heating value of the bipropellant i.e. kerosene/HTP combination are dealt with respectively. Thereafter analysis on the internal energy-flow i.e. energy input, transfer, dissipation and output, during a working cycle of the BHFPE are analyzed. Additionally the operating parameters such as working efficiency, maximum speed of the free piston assembly (FPA) and the output hydraulic energy are derived.

This paper discusses the use of FLUENT to model the flow field of high text peroxide (HTP) as it is catalytically decomposed in the silver screen catalyst bed. 2-D model is used to study the process. The catalytic reacting flow, coupling with heat and mass transfer, is modeled in detail. By modifying physical properties of the H2O2 and H2O, the flow is modeled as single-phase flow. From the HTP monopropellant gas generator system perspective, it is demonstrated that chamber diameter, mass flow rate, and wall condition are important parameters for the design of the gas generator.

Aluminum electrolytic capacitor (AEC) is a widely used capacitor. The casing machine plays an important role in the producing of AEC, and its performance affects the quality of capacitor. This paper introduces the working process and system structure of the typical aluminum electrolytic capacitor casing machine, and analyses some problems of the existing casing machines. Combined with these problems, the paper proposed its future development trends, which provides some references for the design of a new generation of casing machines.