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1
Content available Selecting Parameters to Design Auxiliary Ventilation in Underground Mine
Dang Phuong Thao
Inżynieria Mineralna
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2023
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no. 2, vol. 1
267--270
EN
In recent years, Quang Ninh coal mines are continually expanding on size and depth, the total length of the roadway each year amounts about ten thousands meters in order to reach new production zones. The length of new roadways is usually longer, leading to increase to the airflow demand. Ventilation is one of the main factors effecting driving progress of the roadway. The estimation of airflow requirements is usually based on the minimum amount of airflow required at the heading during driving roadways or at the working face, in other words, when the ventilation ductwork is at its maximum length. Therefore, determination of maximum ventilation length of ductwork has been undertaken. This results allow the selection of a reasonable fan to meet the ventilation requirements when driving the roadway. Also, this value is an important parameter for designing auxiliary ventilation system that operates more efficiently on a lower cost.
2
Content available Experimental investigations on concrete beams reinforced with equivalent service steel pipe
Al-Yassri Labeeb S., Al-Ramahee Munaf A., Al-Khekani Alaa M.
Przegląd Naukowy Inżynieria i Kształtowanie Środowiska
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2021
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Vol. 30, No. 1
16--28
EN
Different techniques were employed for the passage of different utilities through structural elements. The reduction of the overall building weight was the main concern that needs to be achieved, especially for a multistory building. It can be done with the eliminating of a suspended ceiling with a portion of the beam’s weight by taking the advantages of the hollow sections. In this study, an equivalent reinforcement to the traditional ribbed reinforcement was employed to fabricate a reinforced concrete (RC) beam with a hollow section along the length of the beam. A steel pipe was used based on the equivalent moment from section analysis. Two diameters were selected of steel pipes as an equivalent to the commercial reinforcement. A total of four RC beams were cast and tested, two of them with traditional reinforcement and the other with steel pipe reinforcement. The comparison showed a promising result in terms of ductility, cracking pattern, ultimate strength, and mode of failure compared to the reference beam. The peak loads for the specimens with steel pipe were 160.6 kN and 184 kN, while they were 192 kN and 203.5 kN for the beams with traditional reinforcement.
3
Content available Scattering of Sound Waves in Two Stepped Non-uniformly Lined Duct
Tiryakioglu Ayse, Demir Ahmet
Archives of Acoustics
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2020
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Vol. 45, No. 3
511--520
EN
Scattering of sound waves in two stepped cylindrical duct which walls are coated with different acoustically absorbent materials is investigated by using Wiener-Hopf technique directly and by determining scattering matrices. First, by using Fourier transform technique we obtain a couple of modified Wiener-Hopf equations whose solutions involve four sets of infinitely many unknown expansion coefficients providing systems of linear algebraic equations. Then we determine scattering matrices of the problem and we state the total transmitted field by using generalized scattering matrix method. Numerical results are compared for different parameters.
4
Content available Radiation of Sound Waves by a Semi-Infinite Duct with Outer Lining and Perforated End
Tiryakioglu Burhan
Archives of Acoustics
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2020
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Vol. 45, No. 1
77--84
EN
Radiation of sound waves from a semi-infinite cylindrical duct with perforated end whose outer wall is coated with acoustically absorbent material is investigated by using the Wiener-Hopf technique in conjunction with the mode matching technique. A semi-infinite duct with a perforated screen can be used as a model for many engineering applications, such as noise reduction in exhausts of automobile engines, in modern aircraft jet, and turbofan engines. In particular, we aim to find the effects of outer lining and perforated end to sound pressure level for the underlying problem by using the standard Wiener-Hopf and mode matching techniques. We also present some numerical illustrations by determining the sound pressure level for different parameters such as soft and rigid outer surface, with and without perforated end, etc. Such investigations are useful in the reduction of noise effects generated through variety of sources.
5
Content available A study on relationship of duct leakage and parameters of ducts in Quang Ninh mine
Phuong Thao Dang, Vu Chi Dang
Inżynieria Mineralna
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2019
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R. 21, nr 2/2
183--191
EN
Air leakage of auxiliary ventilation ducting systems is the most common reason for the insufficient fresh air in the working face in underground mine. This value is important design parameter for mine auxiliary ventilation system that operates more effectively, with lower cost. Therefore, determination of air leakage along auxiliary ventilation ducting systems has been examined. Also, factors which affect air leakage in the ducting system have been investigated. Experimental data are made on 0.7 m and 1 m diameter ducts over sections of ducts installing towards the working face in Quang Ninh mine.
6
Content available Sound Wave Radiation from Partially Lined Duct
Tiryakioglu Burhan, Demir Ahmet
Archives of Acoustics
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2019
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Vol. 44, No. 2
239--249
EN
The radiation of sound waves from partially lined duct is treated by using the mode-matching method in conjunction with the Wiener-Hopf technique. The solution is obtained by modification of the Wiener-Hopf technique and involves an infinite series of unknowns which are determined from an infinite system of linear algebraic equations. Numerical solution of this system is obtained for various values of the problem parameters, whereby the effects of these parameters on the sound diffraction are studied. A perfect agreement is observed when the results of radiated field are compared numerically with a similar work existing in the literature.
7
Content available Hydrodynamic performance of the horizontal axis tidal stream turbine using RANS solver
Ghassemi H., Ghafari H., Homayoun E.
Zeszyty Naukowe Akademii Morskiej w Szczecinie
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2018
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nr 55 (127)
23--33
EN
This current work investigates the effect of duct and number of blades on the hydrodynamic performance of the horizontal axis tidal stream turbine (HATST). The numerical method based on Reynolds averaged Navier-Stokes (RANS) equations is employed to compare the hydrodynamic performance for various cases of this device. For validation of the numerical results, a 3-blade HATST without-duct has been compared against experimental data. The analysis and comparison of the simulation results show that using duct for HATST has increased the power coefficient, the torque coefficient, the trust coefficient, and the force on the blade. In addition, the simulation results of the cases with a greater number of blades shows that the trust coefficient increased and the force on the blade decreased. Therefore, it is recommended to use ducted HATST with a great number of blades to extract more energy from the tidal stream.
8
Content available remote Research on the pulsatile induced flow in a straight pipe with the MATLAB programming environment
Rydlewicz W., Pałczyński T.
Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka
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2016
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nr 150
61--72
EN
Research on the pulsatile induced flow in a straight pipe was performed at the Institute of Turbomachinery of Lodz University of Technology. The subject under investigation was the influence of orifice plates, which were installed in the inlet of the pipe, on the pressure pulsation levels in this pipe. A substantial amount of measurements involved in the research required automatization of data acquisition and processing. This was achieved by the conversion of the measurement stand, which had previously been created at the Institute of Turbomachinery, followed by preparation of original scripts/software in the MATLAB programming environment.
PL
W Instytucie Maszyn Przepływowych PŁ przeprowadzono badania wpływu kryzowania na wlocie do prostego przewodu rurowego na przebieg zmienności ciśnienia (amplitudę pulsacji ciśnienia) wywołanych wymuszeniem pulsacyjnym w tym przewodzie. Ze względu na dużą liczbę pomiarów zastosowano metody umożliwiające automatyzację akwizycji oraz przetwarzania danych. W tym celu zmodyfikowano istniejące w Instytucie Maszyn Przepływowych stanowisko pomiarowe oraz opracowano autorskie programy w środowisku programistycznym MATLAB.
9
Content available Effects of Duct Shape on Ducted Propeller Thrust Performance
Szafran K., Shcherbonos O., Ejmocki D.
Prace Instytutu Lotnictwa
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2014
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Nr 4 (237) December 2014
84--91
EN
The theory of cooperation with the propeller nozzle is currently being developed as applied to air drives. In the present study attempted to synthesize a new aerodynamic profile for powertrain hovercraft. We analyzed several well-known theoretical solutions aerodynamic airfoils. On the basis of the results, we designed new aerodynamic profile. The new airfoil, which has improved properties in the fields of small and medium speed.
PL
Teoria współpracy z dyszy ze śmigłem lub wentylatorem jest obecnie szeroko rozwijana w zastosowaniu do napędów lotniczych. W niniejszym opracowaniu podjęto próbę syntezy nowego profilu aerodynamicznego dla zespołu napędowego poduszkowca. Przeanalizowaliśmy teoretycznie kilka dobrze znanych rozwiązań profili aerodynamicznych. Na podstawie tych wyników opracowaliśmy nowy profil aerodynamiczny. Nowy profil ma lepsze właściwości w zakresie małych i średnich prędkości. Autorzy przedstawiają teoretyczne wyniki testów porównawczych wybranych profili z nowym profilem Ilot-HR. Nowy tunel wykazuje lepsze właściwości oporowe w porównaniu z dyszą 19A.
10
Content available remote MHD fully developed mixed convection between two long vertical parallel plates
Dubewar A. V., Soundalgekar V. M.
International Journal of Applied Mechanics and Engineering
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2009
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Vol. 14, no 4
941-948
EN
The effect of a transversely applied magnetic field on an MHD fully developed mixed convection between two long vertical parallel plates is studied. Velocity, pressure gradient and bulk-temperature profiles are shown graphically and the effects of different parameters like M (Hartmann number), (buoyancy parameter), (wall temperature difference ratio) on the flow are discussed.
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