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1

Some Effects on the Temperature of the Mine Air at the Heading Face

Nguyen Van Quang, Nguyen Van Thinh, Nguyen Cao Khai, Pham Van Chung

Inżynieria Mineralna

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2021

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no. 2

423--432

EN

Currently, with the increase in mining output leading to deeper mining levels, the volume of heading face serving production has also increased. The thermal environment tends to worsen when digging deep due to the geothermal's effect, which increases the air temperature at the heading face. According to QCVN01/2011-BCT, the temperature at the heading face is not allowed to exceed 300C. To ensure this, in Vietnam today, mainly forced ventilation method uses local fans to provide a clean amount of air to ensure a favorable environment for workers. With the forced ventilation method, the duct position is usually arranged on the side, and the distance from the duct mouth to the heading face is determined to ensure that l < 6√s. In this study, a numerical simulation method by Ansys CFX software is applied to study the influence of several factors such as duct position, air temperature of duct, and roughness characteristics of roadway on the temperature of the mine air at the heading face. The models are set up with six duct positions and four air temperature of duct parameters. Model 1 (y =1.1 m) is better than models 2 to 6 in terms of temperature distribution and the lowest temperature values. Four models have different wind temperatures, and we can see the significant influence of the inlet air temperature of the duct on the thermal environment of the heading face. The results show that with the model T = 297.15K, the temperature value on the roadway length is guaranteed as specified < 303K. The result is a reference for determining the duct position and cool for the high-temperature heading face.

2

Numerical and Experimental Investigation of the Influence of External Wall Moisture on Building Temperature Distributions

Urzędowski Arkadiusz, Zaburko Jacek, Gleń Piotr, Łagód Grzegorz

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 3

297--308

EN

In this paper, the authors made attempt to analyse the influence of moisture in the external wall of a building on the distribution of the temperature field, using numerical and experimental methods. Studies were carried out in the places of heat leakage occurring in structural joints of a single-family residential building, built in the traditional technology. In this study, the thermal bridge parameters were calculated by determining the values of thermal and moisture identifiers. For this purpose, two three-dimensional models of the building partition were designed based on an existing structure, and the boundary conditions for simulations were determined. The obtained heat flux values made it possible to perform quantitative calculations of heat flux distributions and temperatures of construction joints within the thermal bridge occurrence area. Moreover, the accuracy of the final temperatures obtained after combining the mathematical models with the values determined from thermograms was evaluated. In order to validate the results of numerical simulation, a test model was used taking into account the parameters specified in PL-EN 15026. The analysis aimed to present the handiness of using the simulation at the stage of planning the design and thermomodernisation of buildings in the places particularly exposed to adverse terrain and atmospheric conditions.

3

The impact of nozzle configuration on the heat transfer coefficient

Krupanek K., Staszczyk A., Sawicki J., Byczkowska P.

Archives of Materials Science and Engineering

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2018

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Vol. 90, nr 1

16--24

EN

Purpose: The purpose of this paper is to elaborate guidelines regarding geometric configurations of a nozzle manifold that have an impact on the effectiveness of the quenching process and occurrence of quenching distortions. Design/methodology/approach: Within the framework of this study there an optimisation of nozzle manifold geometry was carried out with the help of numerical simulations created using Ansys CFX software. In the first stage, a simplification of the nozzle-sample system reduced to a two-dimensional simulation was employed to determine the most optimal location of the coolant stream. In the second stage, several arrangements of nozzle manifolds were tested in a three-dimensional simulation. The parameters that were taken into account included the rate of sample cooling, the uniformity of cooling with a sample volume and heat coefficient takeover read from its surface. Findings: The different active/inactive nozzle arrangements within the manifold and the impact of the specific arrangements on the uniformity of heat transfer from the sample surface were compared. Research limitations/implications: The simulations carried out within the framework of this study are one of the elaboration stages of a new flow heat treatment technology. Practical implications: The application of an efficient cooling chamber in flow treatment makes it possible to limit quenching distortions to a minimum. An optimal adjustment of cooling parameters and cooling nozzle configuration to the shape of the element in order to make the cooling uniform translate directly into a reduction in distortions. Avoiding the necessity to reduce distortions after quenching means there is a significant reduction in detail production costs (grinding). Originality/value: The concept of single-piece flow in the heat treatment for the mass industry is developing rapidly and constitutes a fully automated element of a manufacturing line, adjusted for the purposes of being included in the production process automatic control system. It also makes it possible to conduct comprehensive and integration quality supervision and management at the level of an individual element, which is not possible in the case of batch heat treatment, which is a gap in the production process.

4

Mathematical model for determining the expenditure of cooling and lubricating fluid reaching directly the grinding zone

Stachurski W., Sawicki J., Krupanek K., Midera S.

Archives of Materials Science and Engineering

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2018

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Vol. 94, nr 1

27--34

EN

Purpose: The purpose of this article is to discuss the method of determining the mathematical model used for calculating the amount of emulsion reaching directly the grinding zone during the hob sharpening process. Design/methodology/approach: The mathematical model, in the form of a multiple regression function, was determined based on the acceptance and rejection method. The data for the calculations was obtained by conducting numerical simulations of fluid flow in the Ansys CFX software. Findings: A mathematical model enables calculating the amount of efficient expenditure of emulsion reaching directly the zone of contact between the grinding wheel and workpiece (hob cutter rake face) at various nozzle angle settings and different nominal expenditures of emulsion. The verification of the mathematical relationship confirmed its accuracy. Research limitations/implications: Further research should focus on the other types of grinding process and other types of cooling and lubricating fluids. Practical implications: The mathematical model enables a selection and application in the workshop and industrial practice of various variants of emulsion supply during the grinding of hob cutter rake face. Analysis of the multiple regression equation created on the basis of the acceptance and rejection method also allows predicting changes in the analyzed numerical model. Originality/value: The literature review has shown that no research of this type has been conducted with regard to analyses and optimisation of the grinding process during hob cutter sharpening. The results of this research are a novelty on a worldwide scale.

5

Projektowanie zaworów z wykorzystaniem modelowania bryłowego

Rogula J.

Przegląd Mechaniczny

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2016

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nr 8

14--19

PL

W artykule zaprezentowano sposób trójwymiarowego konstruowania zaworów 3D z wykorzystaniem programów graficznych INVENTOR oraz SOLID EDGE. Przeprowadzono przykładowe obliczenia numeryczne wytrzymałości korpusu i innych elementów zaworu w celu optymalizacji wymiarowej z uwzględnieniem kształtu kanałów. Analizę naprężeń i wytrzymałości przeprowadzono z użyciem zakładki Metody Elementów Skończonych (MES) programu INVENTOR i Simulation programu SOLID EGDE. Do obliczeń przepływu wykorzystano moduł CFX wersji studenckiej programu ANSYS. Zamodelowano i przeprowadzono obliczenia dla przykładowych typów zaworów: zaworu regulacyjnego i zaworu kulowego.

EN

In the article the ways to perform a valve 3D model with usage of INVENTOR and SOLID EDGE program is presented. The numerical strength calculations of valve body stem and other parts were made to optimize the valve dimensions and the shape of the channels. Stress analysis was performed with module FEM of INVENTOR and Simulation of SOLID EDGE program and CFX of ANSYS. Bali valve and control valve as examples were analyzed.

6

Koncepcja numerycznych i eksperymentalnych badań niestatecznej pracy promieniowego stopnia sprężającego

Kryłłowicz W., Liśkiewicz G.

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

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2010

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nr 137

33-42

PL

Artykuł zawiera przegląd stanu wiedzy w dziedzinie zjawiska pompowania w sprężarkach promieniowych oraz zarys niestacjonarnych badań numerycznych które pozwoliłyby na jego usystematyzowanie. Symulacje numeryczne poparte będą eksperymentami przeprowadzonymi na stanowisku jednostopniowej dmuchawy promieniowej DP.1.12

EN

The article presents the state-of-the-art in understanding of the surge phenomenon in centrifugal compressors and the concept of a non-stationary numerical simulations that will allow to systematize knowledge in that field. Numerical computations will be supported by the experiments conducted on the single stage centrifugal blower DP.1.12.