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A model of the steam compression process in a piston reactor

Joachimiak Damian, Borowczyk Tomasz, Joachimiak Magda

Archives of Thermodynamics

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2023

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Vol. 44, no 4

261--284

EN

The paper discusses the possible determination of steam parameters in a new type of piston machine for steam compression to generate supercritical water parameters. It presents a calculation model that allows one to simulate the process of steam compression in a cylinder with volume regulated by the piston position. In each calculation step, the steam parameters were determined on the basis of fast adiabatic changes which were corrected by the effect of leakage and heat transfer occurrence. The seal of the reactor was assumed to be a compression ring. Depending on the pressure drop on the seal, subcritical and supercritical flow was taken into account. The leak was corrected by the coefficient of flow contraction. Heat transfer was determined by equations for the Nusselt number for water and steam from the homogenous area. The programmed model allows one to simulate changes in the thermodynamic parameters of steam during the process of steam compression with any calculation step. The results presented in this paper show that the application of one compression ring allows us to obtain supercritical steam parameters. Various degrees of sealing leak tightness and their impact on the changeability of steam parameters were analyzed. Heat transfer was shown to have an impact not only on changes in steam temperature, but also on pressure. This paper analyzes the impact of the temperature of the walls of the compression chamber on the value and direction of heat transfer.

2

Modeling of selected design characteristics of cam and hypocycloidal drives of high-pressure fuel pumps

Bor Mateusz, Borowczyk Tomasz, Karpiuk Wojciech, Smolec Rafał

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 2

128--136

EN

The advancement of diesel fuel injection systems is forced by the increasingly stringent exhaust emissions limits. Modern injection systems must generate fuel pressure in excess of 200 MPa, which very often leads to premature wear of the mating components. Generating high pressures results in much force load acting on the pumps. In the case of frequently applied cam-driven pumps, high loads result in significant forces caused by friction. The friction force loads the piston perpendicularly to its axis, which rules out the application of super hard but fragile materials such as ceramics. One of the possible solutions of this problem is the application of unconventional drive systems, the example of which is the hypocycloidal drive. The paper presents the results of simulations comparing selected parameters of the piston motion of the cam-driven pumps and the pumps fitted with hypocycloidal drive. The use of the CAD software also enabled identification of the force acting on the piston (force perpendicular to the piston axis) in the cam-driven pump and its lack in the pump fitted with hypocycloidal drive.

3

Assessment of the possibility of applying ceramic materials in common rail injection systems

Bor Mateusz, Borowczyk Tomasz, Karpiuk Wojciech, Krakowiak Mikołaj, Smolec Rafał

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 1

312--321

EN

Ceramic materials are currently interesting as substitutes for the metals traditionally used for engineering applications. This paper focuses on a comparison of ceramic materials: corundum (alumina, Al2O3) and silicon carbide (solid-state sintered) – SSiC with bearing alloy steel 100Cr6, i.e. the material used to make pistons and cylinders of pumps in common rail injection systems. The article is divided into two parts. In the first part, the aforementioned materials are characterized and their properties compared from the perspective of their application in piston-cylinder assemblies of injection pumps. The second part concerns analysis conduct by means of the finite element method and a specialized simulation environment, based on comparing ceramic materials and bearing steel. This comparison was conducted by using a CAD strength model of a piston in a specific application, being a pump with CP3 design. Simulation results confirmed the beneficial qualities of ceramic materials – the level of material deformation is lower for ceramics in comparison to steel.