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Liquefied natural gas (LNG) is transported by the sea-ships with relatively low pressure (0.13-0.14 MPa) and very low temperature (about 100 K) in cryo-containers. Liquid phase, and the low temperature of the medium is connected with its high exergy. LNG receives this exergy during the liquefaction and is related with energy consumption in this process. When the LNG is evaporated in atmospheric regasifiers (what takes place in many on-shore terminals as well as in local regasifier stations) the cryogenic exergy is totally lost. fortunately, there are a lot of installations dedicated for exergy recovery during LNG regasification. These are mainly used for the production of electricity, but there are also rare examples of utilization of the LNG cryogenic exergy for other tasks, for example it is utilized in the fruit lyophilization process. In the paper installations based on the Brayton cycle gas turbine are investigated, in the form of systems with inlet air cooling, liquid phase injection, exhaust gas based LNG evaporation and mirror gas turbine systems. The mirror gas turbine system are found most exegetically effective, while the exhaust gas heated systems the most practical in terms of own LNG consumption. [ABSTRACT FROM AUTHOR]

In the paper the methodology of furnace exit gas temperature calculations by using well known normative standard method CKTI is presented. There are shown changes in methodology approach for three editions of it and in additional developments. Furnace exit gas temperature for two stoker grate boilers is calculated. By using described methods, it was possible to determine their effectiveness by comparing with measurements. Knowledge of the furnace exit gas temperature allows to define the division into irradiated and convection surfaces, which has an impact on the design features of the boiler as well as its dimensions and weight. [ABSTRACT FROM AUTHOR]

This paper presents the computational fluid dynamics (CFD) model of small-scale a-type Stirling engine. The developed mathematical model comprises of unsteady Reynolds averaged Navier-Stokes set of equations, i.e., continuity, momentum, and energy equations; turbulence was modeled using standard Κ-ω model. Moreover, presented numerical model covers all modes of heat transfer inside the engine: conduction, convection, and radiation. The model was built in the framework of the commercial CFD software ANSYS FLUENT. Piston movements were modeled using dynamic mesh capability in ANSYS FLUENT; their movement kinematics was described based on the crankshaft geometry and it was implemented in the model using user-defined functions written in C programming language and compiled with a core of the ANSYS FLUENT software. The developed numerical model was used to assess the performance of the analyzed Stirling engine. For this purpose, different performance measures were defined, including coefficient of performance (COP), exergy efficiency, and irreversibility factor. The proposed measures were applied to evaluate the influence of different heating strategies of the small-scale α-type Stirling engine. [ABSTRACT FROM AUTHOR]

In this work, we applied the Markov chain Monte Carlo (MCMC) method for the estimation of parameters appearing in the Pennes' formulation of the bioheat transfer equation. The inverse problem of parameter estimation was solved with the simulated transient temperature measurements. A one-dimensional (1D) test case was used to explore the capabilities of using the MCMC method in bioheat transfer problems, specifically for the detection of skin tumors by using surface temperature measurements. The analysis of the sensitivity coefficients was performed in order to examine linear dependence and low sensitivity of the model parameters. The solution of the direct problem was verified with a commercial code. The results obtained in this work show the ability of using inverse heat transfer analysis for the detection of skin tumors. [ABSTRACT FROM AUTHOR]

Despite very rapid development of science in the recent years, the phenomena occurring in the electric arc have not been fully recognized. The main reason for this situation is their the complexity as well as very high temperatures. This paper presents the results of numerical calculations of phenomena which occur in the welding arc. The CFD Fluent package was used for modelling the following phenomena in the electric arc: melting, solidifying, generation of heat and multiphase flows. The 3D Model of a 50 × 30 × 6 mm metal plate segment padded with the use of the MIG method with a wire of 1.2 mm in diameter was developed. The paper focuses on presenting the distribution of temperatures in time, the process of melting and later solidifying of the material, as well as on the transport of the material from the arc to the padding weld. It also shows the initial verification of the model by comparing the results with a picture recorded by thermovisual camera. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to recognise the heat transfer phenomena between an infant placed in a radiant warmer and the surrounding environment. The influence of the parameters in the computational time during different physical phenomena in heat transfer is studied. This model can be also used in future work to improve radiant warmer efficiency. A complete 2D and 3D numerical simulation was carried out using commercial code ANSYS Workbench - ANSYS Fluent. The analysis involved the fluid flow, convection and radiation heat transfer as well as turbulence modeling, although moisture phenomena were omitted. The experiments were completed to validate a numerical solution. [ABSTRACT FROM AUTHOR]

In the paper, the numerical model of the flow phenomena in the flotation machine is presented. The process of flotation consists of a number of phenomena which provide serious numerical difficulties. One can enumerate rotation, two phase flow, foam formation etc. To the knowledge of authors there is no complete numerical model available for the flotation machine. The long-term task of the project is to create a complete model of the machine. Such a model would be very helpful in the process of construction and modernization of the flotation machine. As it was mentioned, due to difficulties connected with modelling the flotation phenomena, only a few aspects of the process were taken under consideration. In the paper, a single phase flow of water is considered. The efficiency of the flotation process strongly depends on the fluid flow field in the machine. The level of mixing the fractions and air bubbles strongly depends on the velocity field of the water, so the proper model of fluid flow is of great practical importance. This paper presents preliminary results of mathematical modelling. The commercial package ANSYS Fluent was utilized for the analysis. The results were compared with the measurements performed on the small scale model of the machine. Obtained results are satisfying and encouraging for further development. [ABSTRACT FROM AUTHOR]