The flange gasket modification of TC SVO1 ion filter manhole on the VVER 440 NPP

Tato diplomová práce se zabývá problematikou záměny těsnění víka nádoby iontového filtru použitého v systému kontinuálního čištění chladiva TC SV01 v jaderné elektrárně s reaktorem VVER 440. Původní niklové těsnění je nahrazeno hřebenovým těsněním s expandovaným grafitem. Výsledky výpočtů jsou vzájemně porovnány a jsou popsány návrhy pro další výpočet. V obecné části je zařazen podrobný popis chemického režimu primárního okruhu spolu s popisem funkce a konstrukce iontových filtrů.This diploma thesis is engaged in replacement of gasket ion filter used in the ion filter of continuous cleaning TC SV01 of rector coolant in nuclear power plants with VVER 440 reactor. Original nickel gasket is replaced by kammprofile gasket with expanded graphite. Calculation results are compared with each other and are described as suggestions for further calculation. The first part included a detailed description of the primary coolant water chemistry, along with a description of the function and structure of ion filter.

Heat Transfer in Small-Scale Channels with Rotating Wall

Tato práce se zabývá problematikou určení koeficientu přestupu tepla v kanálech malých průřezů s rotující stěnou. V rešeršní části práce je popsána specifická geometrie, a to labyrintové těsnění standardně používané v rotačních strojích. Jsou popsány dosavadní kriteriální rovnice stanovující koeficienty přestupu tepla a další parametry v těchto specifických geometriích. V hlavní části je popsáno vybudované experimentální zařízení pro stanovení hodnot tepelných toků a koeficientů přestupu tepla na statoru i rotoru pro daný průtok vzduchu a otáčky rotoru. Následuje prezentování výsledků z provedených experimentů s uvedením odpovídajících kriteriálních rovnic. V další části jsou popsány základní matematické modely inverzních úloh vedení tepla. Jsou provedeny výpočty hustot tepelných toků pomocí těchto inverzních metod a porovnány s referenčními experimentálně zjištěnými hustotami tepelných toků.This work deals with the determination of the heat transfer coefficient in small channels with a rotating wall. The research part of the thesis is focused on specific geometry, namely labyrinth seals used in rotary machines. Existing criteria equations determining heat transfer coefficients and other parameters in these specific geometries are described. The central part describes the built experimental device for the determination of values of heat flows and heat transfer coefficients on both stator and rotor for given airflow and rotor speed. The following section is devoted to presenting the results of the performed experiments with the corresponding criteria equations. The next part describes the basic mathematical models of inverse heat conduction problems. Calculations of heat flux using these inverse methods are performed and compared with reference heat flux sensors.

Methods 3D laser scanning workpieces in process plan

Tato práce je zaměřena na problematiku 3D laserového skenování obrobků, jako jedné z možností postprocesní kontroly. Po uvedení základních principů pro získání 3D modelu tělesa, následuje popsání hlavních komponentů těchto skenerů. Poté následuje samotné rozdělení skenerů popsáním jednotlivých typů.This work is aimed at problem of 3D laser scanning workpieces as one of possibility post - procedural verification. After the presentation of philosophy for obtaining 3D shape of body follows diagnosis of the chief components these scanners. After it follows a himself division of scanners and diagnosis single types.

LONG-TERM LIQUID TRANSFER MEASUREMENTS OF FALLING FILM HEAT AT HORIZONTAL TUBE BUNDLE

This paper presents the current research on heat transfer at a sprinkled tube bundle consisting of smooth tubes and located in a chamber inside of which a low pressure is created by an exhauster. It also monitors the changes of the heat transfer coefficient in relation to the speed of sprinkled and sprinkling liquid flow, thermal gradient and low pressure inside the chamber. This articles shows and compares extensive measurements in condensation and evaporation modes

POSSIBILITIES OF USING THERMOGRAVIMETRIC ANALYSIS FOR ENERGETIC

Energy Engineering brings together a wide range of scientific disciplines. In energetic industry, thermal analysis can be used for determining of properties of fuels, construction materials, seal, ash and others. This research is focused especially on measurement of fuel properties and mass changes of fuel during combustion. As fuel was using biomass, especially it was pellets of rape. Second aim of research is observation of mass changes in ash. Good knowledge of the energy properties of fuels seems to be very important for the proper design of combustion and gasification facilities. Thermogravimetric analysis (TGA) is one of methods of thermal analysis. TGA is one of the advanced methods for testing materials and fuels by temperature increase. In thermo gravimetric analyser, it is possible to simulate thermal conditions which are similar to conditions by combustion or gasification. Thanks to the accurate measurement of weight loss and record of measured data we can deduce changes that fuel material undergoes during these processes

Heat Exchangers for Condensation and Evaporation Applications Operating in a Low Pressure Atmosphere

This paper presents a state-of-the-art study of a heat transfer process in liquid spraying heat exchangers placed in a vacuum chamber. The experimental case studied here describes the behavior of a falling film evaporation and condensation mode on horizontal tube bundles. The study aims to obtain the heat transfer coefficient and its correlations by means of a mathematical model

Automatic biomass boiler with an external thermoelectric generator

Abstract. This paper presents the design and test results of an external thermoelectric generator that utilizes the waste heat from a small-scale domestic biomass boiler with nominal rated heat output of 25 kW. The low-temperature Bi2Te3 generator based on thermoelectric modules has the potential to recover waste heat from gas combustion products as effective energy. The small-scale generator is constructed from independent segments. Measurements have shown that up to 11 W of electricity can be generated by one segment. Higher output power can be achieved by linking thermoelectric segments. The maximum output power is given by the dew point of the flue gas. The electrical energy that is generated can be used, e.g., for power supply or for charging batteries. In the near future, thermoelectric generators could completely eliminate the dependence an automated domestic boiler system on the power supply from the electricity grid, and could ensure comfortable operation in the event of an unexpected power grid failure

Influence of temperature on the production and size distribution of fine particles released from beech wood samples

This study deals with laboratory investigation of fine particulate matter production over controlled heating of beech wood samples in the atmosphere with 21% of oxygen. From carried out measurements follow that majority of emitted fine particles is in the range 40 nm to 500 nm. The peak number of particles is between 100 nm an 300 nm. The mass concentration of produced particulate matter increases proportionally with increasing size of the sample. The number of particles is increasing too, but not proportionally. In the second step, the samples in form of sawdust, bark and heartwood were analyzed from the view of particulate matter production. Obtained results are strongly influenced by actual combustion conditions that significantly differ between wood samples forms. It is not easy to find any clear trend between temperature and size distribution of produced particles. From the general view, the bark produces higher number concentration of ultrafine particles in comparison with heartwood and sawdust sam

Parameters Influencing the Emission of Ultrafine Particles during 3D Printing

This paper presents a complex and extensive experimental evaluation of fine particle emissions released by an FDM 3D printer for four of the most common printing materials (ABS, PLA, PET-G, and TPU). These thermoplastic filaments were examined at three printing temperatures within their recommended range. In addition, these measurements were extended using various types of printing nozzles, which influenced the emissions considerably. This research is based on more than a hundred individual measurements for which a standardized printing method was developed. The study presents information about differences between particular printing conditions in terms of the amount of fine particles emitted as well as the particle size distributions during printing periods. This expands existing knowledge about the emission of ultrafine particles during 3D printing, and it can help reduce the emissions of these devices to achieve cleaner and safer 3D printer operations