Search Results

You are looking at 1 - 5 of 5 items for

  • Author: František Dzianik x
Clear All Modify Search
Open access

František Dzianik

Approximate Model of Zone Sedimentation

The process of zone sedimentation is affected by many factors that are not possible to express analytically. For this reason, the zone settling is evaluated in practice experimentally or by application of an empirical mathematical description of the process. The paper presents the development of approximate model of zone settling, i.e. the general function which should properly approximate the behaviour of the settling process within its entire range and at the various conditions. Furthermore, the specification of the model parameters by the regression analysis of settling test results is shown. The suitability of the model is reviewed by graphical dependencies and by statistical coefficients of correlation. The approximate model could by also useful on the simplification of process design of continual settling tanks and thickeners.

Open access

František Dzianik and Štefan Gužela

Abstract

The paper deals with the hydrodynamic properties, i.e. the consumption of mechanical energy expressed by pressure drops within a helium loop intended for the testing of decay heat removal (DHR) from the model of a gas-cooled fast reactor (GFR). The system is characterised by the natural circulation of helium, as a coolant, and assume steady operating conditions of circulation. The helium loop consists of four main components: model of gas-cooled fast reactor, model of the heat exchanger for decay heat removal, hot piping branch and cold piping branch. Using the process hydrodynamic calculations, the pressure drops of circulating helium within the main components of the helium loop were determined. The calculations have been done for several defined operating conditions which correspond to the different helium flow rates within the system.

Open access

Štefan Gužela and František Dzianik

Abstract

There are the various types of heat exchangers. The selection of the heat exchanger right type is the first basic assumption for its optimal operation. The heat exchanger calculation itself is another prerequisite for its optimal operation. This article deals with the variables which are usually used to describe the stationary operation of any recuperative heat exchanger with two incoming and two outgoing streams. The knowledge of these variables, including the facts resulting from them, is necessary not only from the point of view of the calculation but also from the point of view of the evaluation of the experimental data of any heat exchanger. The variables values needed for the calculation of heat exchangers, so-called key variables, must always fall within the values range determined on the basis of generally valid knowledge about heat exchangers. The article also deals with the determination of the limit values defining the values range of these key variables.

Open access

František Dzianik, Štefan Gužela and Eva1 Puškášová

Abstract

The paper deals with the process properties in terms of the heat transfer, i.e. the thermal performance of the thermal-process units within a helium loop intended for the testing of the decay heat removal (DHR) from the model of the gas-cooled fast reactor (GFR). The system is characterised by a natural circulation of helium, as a coolant, and assume the steady operating conditions of the circulation. The helium loop consists of four main components: the model of the gas-cooled fast reactor, the model of the heat exchanger for the decay heat removal, hot piping branch and cold piping branch. Using the thermal calculations, the thermal performance of the heat exchanger model and the thermal performance of the gas-cooled fast reactor model are determined. The calculations have been done for several defined operating conditions which correspond to the different helium flow rates within the system.

Open access

Štefan Gužela, František Dzianik, Martin Juriga and Juraj Kabát

Abstract

Nowadays, the operating nuclear reactors are able to utilise only 1 % of mined out uranium. An effective exploitation of uranium, even 60 %, is possible to achieve in so-called fast reactors. These reactors commercial operation is expected after the year 2035. Several design configurations of these reactors exist. Fast reactors rank among the so-called Generation IV reactors. Helium-cooled reactor, as a gas-cooled fast reactor, is one of them. Exchangers used to a heat transfer from a reactor active zone (i.e. heat exchangers) are an important part of fast reactors. This paper deals with the design calculation of U-tube heat exchanger (precisely 1-2 shell and tube heat exchanger with U-tubes): water – helium.