Górnictwo i Geoinżynieria
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ISSN 1732-6702
Issue Date
2010
Volume
R. 34
Number
Nr 1
Description
Journal Volume
Górnictwo i Geoinżynieria
R. 34 (2010)
Projects
Pages
Articles
Analiza rozwoju uszkodzenia i trwałych odkształceń próbek dolomitu poddanych quasistatycznym jednoosiowym obciążeniom
(Wydawnictwa AGH, 2010) Cieślik, Jerzy
This paper presents results of uniaxial quasistatic compression tests of dolomite samples. The main topic addressed was the analysis of rock samples failure in macro scale and observation of some micro mechanical failure processes effects. The micro mechanical processes (fracture or rock and grain slips) was analyzed by irreversible strain observation and calculated as different energy dissipation during loading and unloading of rock samples. A relationship between these micro mechanical failure processes and axial and lateral irreversible strain was shown in various strain rate loading conditions. All the tests were performed for a range of pre failure stress strain characteristics only.
Wpływ profilu prędkości powietrza na parametry przepływu dwufazowego w szybie wentylacyjnym
(Wydawnictwa AGH, 2010) Branny, Marian; Nowak, Bernard; Ptaszyński, Bogusław; Kuczera, Zbigniew; Łuczak, Rafał; Życzkowski, Piotr
Several inflows of water beyond shaft brickwork occur frequently on the length of the upcast shaft. The article describes the results of influence of air velocity profile on the parameters of two-phase flow in the upcast shaft for accepting constant discharge of water flows to the cross-section of shaft with water drops diameter: 0,5 mm, 1 mm, 2 mm, 3 mm.
Analiza pola prędkości w wyrobiskach przewietrzanych przez dyfuzję
(Wydawnictwa AGH, 2010) Branny, Marian; Filipek, Wiktor; Karch, Michał
Ventilation of short blind heading caused by through road air velocity is considered. A series of numerical tests was performed to determine the effect of different through air velocities on airflow patterns. The velocities ranged between 0,65 m/s and 2,1 m/s. 3D velocity fields was calculated using a finite-volume CFD computer code FLUENT 6.1. Two turbulence models (standard k- and RNG k-) as well as two near-wall models (wall function and enhanced wall treating) were tested. Numerical results were compared with experimental data.
Zmiana temperatury wody chłodzącej skraplacz górniczej chłodziarki powietrza w wentylatorowej chłodnicy wyparnej
(Wydawnictwa AGH, 2010) Nowak, Bernard; Filek, Krzysztof
The work treats of ventilator evaporative cooler of water, which is intended for cooling of mine compressor air cooler condenser. From mass and enthalpy balances of medium flowing through the cooler (air, cooling water and spraying water) the equations from mathematical model for steady state were introduced; the spread in space character of medium parameter changes in the cooler was not taken into account but its concentrated character and connected with that fact jumping changes were accepted. In the work, the results of example calculations were made by using computer program, which is created on the basis of introduced mathematical equations of cooler description. 27 variants, which are differed from each other in parameter values of medium at the inlet of cooler, were studied. Results of calculations are compiled in a table.
Wartości współczynników wymiany ciepła i masy w wentylatorowej wyparnej chłodnicy wody
(Wydawnictwa AGH, 2010) Nowak, Bernard; Filek, Krzysztof; Branny, Marian
Results of experimental studies of the performance of fan evaporative type of water coolers are presented in this paper. Tests were conducted with two types of coolers - RK-450 and CWW-420. Parameters of cooled and spray water and of the air were measured. On the base of data collected during laboratory experiments, coefficients of heat and mass exchange were calculated for both tested coolers. Among this coefficient are: overall heat-transfer coefficient through membrane (k), convective heat-transfer coefficient (alpha) and coefficient of mass exchange (P) between spray water and the air. There were determined regression lines and coefficients of linear correlation for k and a in dependence of inlet water temperature. The results of experiments and calculations are presented in the form of plots and tables.