Comparison of heat losses calculation by CSN 06 0210 and CSN EN 12831

Diplomová práce se zabývá porovnáním výpočtů tepelných ztrát pomocí norem ČSN 06 0210 s ČSN EN 12831. Součástí práce je seznámení s problematikou výpočtu tepelných ztrát včetně definice základních pojmů, podrobný rozbor výpočtů podle každé z norem, definice objektů pro porovnávací výpočet a výpočet tepelných ztrát a potřeby tepla pro vytápění posuzovaných objektů podle jednotlivých norem. Na závěr práce je provedeno porovnání a diskuze výsledků získaných pomocí výpočtů dle obou norem.The diploma thesis deals with comparison of heat loss calculation by CSN 06 0210 and CSN EN 12831. This work contains short introduction to the heat loss calculation, definition of basic terms, detailed analysis of heat loss calculation by both standards, description of exemplar buildings, heat loss calculation and heat requirement for heating of buildings according to particular standards. At the end of the work the comparison and discussion of calculation results is presented.

Transport and Deposition of Aerosol in Human Respiratory Tract

Jednou z možných cest léčby nemocí dýchacího ústrojí je použití léku ve formě aerosolu. Jedná se o neinvazivní a rychlý způsob jak dopravit lék do požadované části tracheobronchiálního stromu nebo do krevního oběhu. Ačkoliv se metoda dávkování léků pomocí inhalátorů a nebulizérů používá již delší dobu, stále se řeší otázka účinnosti této metody. Značná část takto dopravovaných léků se nedostane do svého zamýšleného cíle a deponuje v oblastech, kde jejich působení nevyžadujeme. Cílem této práce je pomoci k řešení otázky průchodnosti monodispersního, homogenního aerosolu obsahujícího částice mikronových velikostí skrze horní část dýchacích cest. Tato práce byla vypracována s využitím numerických simulací provedených metodou konečných objemů v programu na bázi výpočtové mechaniky kontinua. Turbulence byla modelována metodou Reynoldsova středování Navier – Stokesových rovnic s využitím dvourovnicového modelu k-omega SST. Výsledkem práce je analýza proudění během dvou zvolených dýchacích režimů s ohledem na stacionární i cyklický průběh proudění a jejich porovnání s experimenty na totožných geometriích. Dále byla provedena rešerše zjednodušených modelů plic a jejich geometrie použita při výpočtu distribuce vzduchu v modelu dýchacích cest. V závěru práce je pak proveden výpočet depozice aerosolu a proveden rozbor jeho výsledků.One of approaches in treatment of respiratory system diseases is the use of drug particles suspended in air in the form of aerosol. It is a fast and non-invasive method for the delivery of medicine into tracheobronchial tree or bloodstream. Although the method of the medication dosage by means of inhalers or nebulizers is well known, the effectiveness of that approach is still an actual issue. A significant amount of drugs delivered with the use of the medication dosage never reaches its primary destination and the drugs deposit in antecendent areas of respiratory tract where their presence is not required. This thesis deals with a problem of the passage of monodisperse homogenous aerosol with micron-size particles through the upper parts of the respiratory tract. This work was created with the use of numerical simulations carried out by means of the finite volume method in the commercial code based on computational fluid dynamics. Turbulence was modelled using the Reynolds averaged Navier–Stokes equations with the two-equation eddy viscosity k-omega SST model. The main output of the thesis is the analysis of airflow in two respiratory regimes. Stationary and cyclic cases of the flow behaviour were considered and the validation of simulated results with experiments performed on similar geometries was carried out. Furthermore, the review of simplified lung models and their geometries was made and the acquired results were used for the calculation of air distribution in the respiratory tract. The last part of the thesis deals with the calculation of particle deposition and with the analysis of the results.

Effect of multiple liquid inlets on mass transfer in rotating packed beds

This study deals with optimalization of rotating packed bed design using computational fluid dynamics approach. Comparison of three variants of liquid distributor were performed on 2D geometry. Turbulence was modelled using unsteady RANS approach and volume of fluid technique were used to simulate gas-liquid interphase. Results were compared on basis of liquid holdup evaluation

Simulation of Airway Deposition of an Aerosol Drug in COPD Patients

Medical aerosols are key elements of current chronic obstructive pulmonary disease (COPD) therapy. Therapeutic effects are conditioned by the delivery of the right amount of medication to the right place within the airways, that is, to the drug receptors. Deposition of the inhaled drugs is sensitive to the breathing pattern of the patients which is also connected with the patient's disease severity. The objective of this work was to measure the realistic inhalation profiles of mild, moderate, and severe COPD patients, simulate the deposition patterns of Symbicort((R)) Turbuhaler((R)) dry powder drug and compare them to similar patterns of healthy control subjects. For this purpose, a stochastic airway deposition model has been applied. Our results revealed that the amount of drug depositing within the lungs correlated with the degree of disease severity. While drug deposition fraction in the lungs of mild COPD patients compared with that of healthy subjects (28% versus 31%), lung deposition fraction characteristic of severe COPD patients was lower by a factor of almost two (about 17%). Deposition fraction of moderate COPD patients was in-between (23%). This implies that for the same inhaler dosage severe COPD patients receive a significantly lower lung dose, although, they would need more

The role of the combined use of experimental and computational methods in revealing the differences between the micron -size particle deposition patterns in healthy and asthmatic subjects

Quantification of airway deposition of aerosol particles is essential for the assessment of health risks of detrimental particles. Knowledge of deposition distribution is important also in the case of treatment with aerosolised drugs. It is also worth considering that deposition of inhaled particles in severe asthmatics can be different from the deposition in healthy subjects due to the modified breathing parameters, airway geometry and lobar flow distribution. The aim of this study was to apply combined experimental and numerical techniques to quantify the upper airway and bronchial deposition of the inhaled microparticles in healthy individuals in comparison with asthma patients. Idealised and realistic physical and digital replicas of the human airways were constructed. Deposition fractions and efficiencies of inhaled polydisperse mannitol and chitosan particles in different airway sections were measured and calculated. Deposition fraction of polydisperse mannitol particles in the idealised airway geometry assuming breathing conditions of healthy subjects was 21.9% and 18.3% when determined experimentally and by numerical simulations, respectively. Experimental measurements of deposition fraction of chitosan particles in the same geometry, but assuming breathing parameters characteristic of severe asthmatics yielded 32%, while simulations provided 30.1% for the same conditions. Extrathoracic deposition fraction of mannitol particles in healthy subjects measured in the realistic geometry was 71.1%, while bronchial deposition fraction was 5.3%. The corresponding simulations yielded 76.2% and 8.9% deposition fractions in the upper and bronchial airways, respectively. There was a good agreement between the experimental and simulation deposition results also in the different predefined sections of the airways. Present pilot study proved that lobar flow redistribution due to severe asthma significantly modified the deposition distribution of micro-particles. Although the present results refer only to small groups of healthy and asthmatic individuals, it clearly demonstrates the capability of carefully validated models to simulate the deposition of micron-size particles in larger populations of both groups

Inhalers and nebulizers: basic principles and preliminary measurements

Inhalers are hand-held devices which are used for administration of therapeutic aerosols via inhalation. Nebulizers are larger devices serving for home and hospital care using inhaled medication. This contribution describes the basic principles of dispersion of aerosol particles used in various types of inhalers and nebulizers, and lists the basic physical mechanisms contributing to the deposition of inhaled particles in the human airways. The second part of this article presents experimental setup, methodology and preliminary results of particle size distributions produced by several selected inhalers and nebulizers

Numerická simulace proudění v realistickém modelu horních cest dýchacích

This article deals with CFD calculations of flow patterns in a realistic model of the upper respiratory tract. RANS method was used for the calculation. The flow was solved as an unsteady one due to its nature. Two breathing cycles were simulated, 15 l/min which corresponds to the idle breathing mode and 30 l/min which corresponds to light activity. The model of upper airways consists of the oral cavity, larynx and trachea, which branches up to the fourth generation. Values of the velocity field distribution calculated are the basis for future calculations of aerosol transport and deposition in the human respiratory tract.Tato práce se zabývá CFD výpočtem proudových polí v realistickém modelu horních cest dýchacích. Pro výpočet byla použita metoda RANS. Vzhledem k povaze proudění byl výpočet řešen jako nestacionární. Simulovány byly dva režimy dýchání, dechový objem 15 l/min, který odpovídá klidovému režimu dýchání a 30 l/min, který odpovídá lehké aktivitě. Model horních cest dýchacích sestává z ústní dutiny, hrtanu a trachey, která se dále větví až do čtvrté generace větvení. Vypočtené hodnoty rozložení rychlostních polí jsou základem pro budoucí výpočty transportu a depozice aerosolů v dýchacím ústrojí člověka