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Results of an extensive experimental study conducted in eighties at the former Leningrad Polytechnic Institute are revised and analysed in context of some further research. The optimum length of straight outlet tubes with diffuser of circular cross-section and the outlet/inlet crosssectional area ratio are established. The optimum geometrical features of cranked type outlet tubes and the outlet tubes...
An experimental investigation of the turbulent flow over a flat plate in a subsonic wind tunnel was carried out. The enhanced level of turbulence was generated by five wicker grids with square meshes, and different parameters (diameter of the grid rod 0.3–3 mm and the grid mesh size 1–30 mm). The velocity of the flow was measured by means of a 1D hot-wire probe, suitable for measurements in a boundary...
The specific issues that occur in the mathematical modelling of a spray-ejector condenser have been presented. The results of a thermodynamic analysis of a steam-gas turbine cycle have been obtained by computational flow mechanics code. The main aim of the spray-ejector condenser is simultaneously condensing steam and compressing CO2 from the condensation pressure to about 100 kPa. Hence, the most important...
A numerical investigation to discuss the effects of radiation and variable viscosity on heat and mass transfer characteristics of natural convection over a horizontal surface embedded in a saturated porous medium in the presence of internal heat generation is carried out in this study. The working fluid for the investigation is optically thick gray gas. The Dufour and Soret effects are also taken into...
The paper presents the accurate assessment of the amount of gas flowing through three types of aero-engine expander sealing. Structures consisting of straight-through labyrinth seals – with one, two and three fins are considered. The study deploys two independent approaches. The first one focuses on the experimental research using high-precision test section with non-rotating labyrinth seals specimen...
Organic Rankine cycle (ORC) is considered the most used technology in low temperature heat recovery units for cogeneration (electricity and cold). In this study, the effect of the operating parameters, in particular the condensation and the vaporization temperatures on the performance of the cycle are analyzed. In addition, we developed a new combination of organic Rankine cycle and vapor compresion...
This paper presents a novel, procedure of calculations of simple thermodynamic cycles with the main isothermal expansion process. Calculation assumptions are based on the use of technologically advanced flow devices. Firstly the theoretical Ericsson cycle with description of isothermal process has been presented. Then the calculations for open gas cycle with external combustion chamber, realising...
Developments in construction engineering (new materials, construction techniques) facilitate the design of very flexible, light structures with low damping which unfortunately results in higher susceptibility of these structures to wind action. It is therefore necessary to use more accurate scientific tools in the engineering phase of these structures. Analytical methods for considering wind effects...
Cogeneration of electric energy and heat as well as seasonal changes of the condenser pressure in low-pressure extraction/condensing turbines require adaptive control to adapt the geometry of the blading system to the changing flow conditions. In this paper adaptive control is achieved by means of restaggering (rotating) adjustable stator blades. An increase of turbine efficiency and power coming from...
The work presents the thermal dynamics of the building. The mathematical model covers the issues of heat exchange and temperature control in the room due to changing environmental conditions. The presented work describes the operation of the control system due to thermal losses and thermal inertia of the building. Mathematical model introduces a new method of thermal loss analysis in the conditions...
In the wake of much needed energy transformation, European Union urges member states to take action for supporting microgeneration. As Poland introduced novel to Renewable Energy Act in mid-2018, microgeneration systems of up to 50 kWe installed can benefit from a prosumer scheme. This paper investigates scenarios for installation of a hybrid system composed of a microcogeneration unit and a photovoltaic...
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