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Evaluation of the heat transfer performance of helical coils of non-circular tubes

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Journal of Zhejiang University-Science A(Applied physics & Engineering) 2011年第1期12卷 63-70页

作者： Jundika C.KURNIA agus p.sasmito Arun S.MUJUMDAR Department of Mechanical Engineering National University of Singapore Mineral Metal and Material Technology CentreNational University of Singapore

This study addresses heat transfer performance of various configurations of coiled non-circular tubes, e.g., in-plane spiral ducts, helical spiral ducts, and conical spiral ducts. The laminar flow of a Newtonian fluid in helical coils made of square cross section tubes is simulated using the computational fluid dynamic approach. The effects of tube Reynolds number, fluid prandtl number, coil diameter, etc., are quantified and discussed. Both constant wall temperature and constant heat flux conditions are simulated. The effect of in-plane coil versus a cylindrical design of constant coil, as well as a conical coil design is discussed. Results are compared with those for a straight square tube of the same length as that used to form the coils. Advantages and limitations of using coiled tubes are discussed in light of the numerical results.

关键词： Coil Non-circular tube Heat transfer performance Mathematical model

Freezing on demand: A new concept for mine safety and energy savings in wet underground mines

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International Journal of Mining Science and Technology 2019年第4期29卷 621-627页

作者： Mahmoud A.Alzoubi Ahmad Zueter Aurelien Nie-Rouquette agus p.sasmito Department of Mining and Materials Engineering McGill University

The artificial ground freezing(AGF)systems are designed to operate continuously for an extended period of time to control the groundwater seepage and to strengthen the groundwater structure surrounding excavation *** mode of operation requires a massive amount of energy to sustain the thickness of the frozen ***,it is of great interest to propose new concepts to reduce energy consumption while providing sufficient structural stability and safe *** paper discusses the principle of the freezing on demand(FoD)by means of experiment and mathematical model.A lab-scale rig that mimics the AGF process is conceived and *** setup is equipped with more than 80 thermocouples,flow-meters,and advanced instrumentation system to analyze the performance of the AGF process under the FoD concept.A mathematical model has been derived,validated,and utilized to simulate the transient FoD *** results suggest that the overall energy saving notably depends on the coolant’s temperature;the energy saving increases while decreasing the coolant inlet ***,applying the FoD concept in an AGF system leads to a significant drop in energy consumption.

关键词： Artificial ground freezing Freezing on demand Energy saving Conjugate heat transfer porous media

Friction factor correlation for airflow through broken rocks and its applications in mine ventilation

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International Journal of Mining Science and Technology 2020年第4期30卷 455-462页

作者： Leyla Amiri Seyed Ali Ghoreishi-Madiseh Ferri p.Hassani agus p.sasmito Department of Mining and Materials Engineering McGill UniversityMontrealQuebec H3A 2A7Canada Norman B.Keevil Institute of Mining Engineering University of British ColumbiaVancouverBritish Columbia V6T 1Z4Canada

The Atkinson equation along with its friction factor is commonly used to estimate pressure requirement in mine ***,friction factor correlation of flow through broken rock,typically found in blasted stope,gob,rock pit or block caving rock deposits,etc.,is currently ***,it is impractical to conduct direct measurements of flow resistance in an inaccessible broken rock *** paper aims to develop a new friction factor correlation of flow through broken rock that can be used directly in Atkinson *** proposed correlation is valid for broken rocks with diameter between 0.04 and 1.2 m and porosity ranging from 0.23 to 0.7.

关键词： Broken rock Fractured rock packed rock bed Large particle pressure drop Friction factor

Experimental investigation on the effects of microwave irradiation on kimberlite and granite rocks

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第2期13卷 267-274页

作者： Samir M.Deyab Hamed Rafezi Ferri Hassani Mehrdad Kermani agus p.sasmito Department of Mining and Materials Engineering McGill UniversityMontrealCanada

This study is a part of an overall research project on the effects of microwave(MW)irradiation on rocks for assisted rock breaking systems as well as mineral processing at McGill *** the first time,this paper highlights a comprehensive investigation on the effects of microwave irradiation on Canadian *** contribution to the continuous rock excavation and rock weakening effect prior to implementation of mechanical techniques was *** different kimberlite rocks,*** kimberlite(VK)and hypabyssal kimberlite(HK),and granite samples were *** important physical properties of the rock samples were measured including rock quality designation(RQD),specific gravity,porosity,and specific heat *** samples were treated for various exposure times using a multi-mode MWunit at different power levels ranging from 2 kW to 15 *** effect of MW irradiation on rock samples was *** results indicate that the mechanical properties including unconfined compressive strength(UCS)and Brazilian tensile strength(BTS)were significantly dropped as a result of ***,the effect on rock abrasivity using the Cerchar abrasivity index(CAI)has also been discussed.

关键词： Microwave irradiation Kimberlite Rock excavation Rock strength Abrasivity

Numerical and experimental analyses of rock failure mechanisms due to microwave treatment

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第10期15卷 2483-2495页

作者： Haitham M.Ahmed Adel Ahmadihosseini Ferri Hassani Mohammed A.Hefni HussinA.M.Ahmed Hussein A.Saleem Essam B.Moustafa agus p.sasmito Mining Engineering Department King Abdulaziz UniversityJeddah21589Saudi Arabia Department of Mining and Materials Engineering McGill UniversityMontrealQCH3A0E8Canada Mechanical Engineering Department King Abdulaziz UniversityJeddah21589Saudi Arabia

Despite the extensive studies conducted on the effectiveness of microwave treatment as a novel rock preconditioning method,there is yet to find reliable data on the rock failure mechanisms due to microwave *** addition,there is no significant discussion on the energy efficiency of the method as one of the important factors among the mining and geotechnical engineers in the *** study presents a novel experimental method to evaluate two main rock failure mechanisms due to microwave treatment without applying any mechanical forces,*** and concentrated *** result shows that the existence of a small and concentrated fraction of a strong microwave absorbing mineral will change the failure mechanism from the distributed heating to the concentrated heating,which can increase the weakening over microwave efficiency(WOME)by more than 10 *** observation is further investigated using the developed coupled numerical *** is shown that at the same input energy,the existence of microwave absorbing minerals can cause major heat concentration inside the rock and increase the maximum temperature by up to three times.

关键词： Microwave treatment Numerical modeling Failure mechanism Energy efficiency Rock pre-conditioning

Diesel generator exhaust heat recovery fully-coupled with intake air heating for off-grid mining operations:An experimental,numerical,and analytical evaluation

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International Journal of Mining Science and Technology 2022年第1期32卷 155-169页

作者： Durjoy Baidya Marco Antonio Rodrigues de Brito agus psasmito Seyed Ali Ghoreishi-Madiseh Norman B.Keevil Institute of Mining Engineering The University of British ColumbiaVancouver V6T 1Z4Canada Department of Mining and Materials Engineering McGill UniversityMontreal H3A 2A7Canada

The customarily discarded exhaust from the fossil fuel-based power plants of the off-grid mines holds the thermal potential to fulfill the heating requirement of the underground *** present research fills in an important research gap by investigating the coupling effect between a diesel exhaust heat recovery and an intake air heating system employed in a remote *** integrative approach comprising analytical,numerical,and experimental assessment has been *** novel analytical model developed here establishes the reliability of the proposed mine heating system by providing comparative analysis between a coupled and a decoupled *** effect of working fluid variation has been examined by the numerical analysis and the possible improvement has been *** investigations present a demonstration of the successful lab-scale implementation of the concept and validate the numerical and analytical models *** deployment of the fully coupled mine heating system proposed here will assist the mining industry on its journey towards energy-efficient,and sustainable mining practices through nearly 70%reduction in fossil fuel consumption for heating intentions.

关键词： Remote mines Waste heat utilization Diesel exhaust Combined heat and power generation Clean energy in mining Coupled heating system

Guest editorial-special issue on advances in mine ventilation in 2019

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International Journal of Mining Science and Technology 2020年第4期30卷 441-441页

作者： agus p.sasmito Seyed Ali Ghoreishi-Madiseh Ferri Hassani Jozef Stachulak Department of Mining and Materials Engineering McGill UniversityMontreal H3A 0E8Canada Norman B.Keevil Institute of Mining Engineering The University of British ColumbiaVancouver V6T 1Z4Canada Mirarco Mining Innovation Sudbury P3E 2C6Canada

Ventilation has always been an integral part of underground mining *** surface and shallow deposits are depleting,extracting ores from deeper underground levels is becoming more and more common,and is expected to grow in the future[1].Rising environmental awareness,energy cost and implementation of carbon tax in some countries have led the mining industry to look for cleaner alternatives[2].

关键词： underground shallow mining

prediction of air flow, methane, and coal dust dispersion in a room and pillar mining face

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International Journal of Mining Science and Technology 2017年第4期27卷 657-662页

作者： Lu Yueze Akhtar Saad sasmito agus p. Kurnia Jundika C. Department of Mining and Materials Engineering McGill University Department of Mechanical Engineering Universiti Teknologi PETRONAS

In underground coal mines, uncontrolled accumulation of methane and fine coal dust often leads to serious incidents such as explosion. Therefore, methane and dust dispersion in underground mines is closely monitored and strictly regulated. Accordingly, significant efforts have been devoted to study methane and dust dispersion in underground mines. In this study, methane emission and dust concentration are numerically investigated using a computational fluid dynamics(CFD) approach. Various possible scenarios of underground mine configurations are evaluated. The results indicate that the presence of continuous miner adversely affects the air flow and leads to increased methane and dust ***, it is found that such negative effect can be minimized or even neutralized by operating the scrubber fan in suction mode. In addition, it was found that the combination of scrubber fan in suction mode and brattice results in the best performance in terms of methane and dust removal from the mining face.

关键词： Dust Methane Mine ventilation Mining machine

Dust dispersion and management in underground mining faces

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International Journal of Mining Science and Technology 2014年第1期24卷 39-44页

作者： Kurnia Jundika Candra sasmito agus pulung Mujumdar Arun Sadashiv Minerals Metals and Materials Technology Centre National University of Singapore Mechanical Engineering Masdar Institute of Science and Technology Department of Mining and Materials Engineering McGill University Department of Bioresource Engineering McGill University

presence of fine dust in air causes serious health hazard for mine operators resulting in such serious problems as coal workers’pneumoconiosis and *** sources of dust appear of course along the mining face where the minerals are *** control and management are required to ensure safe working environment in the ***,we utilize the computational fluid dynamic(CFD)approach to evaluate various methods used for mitigating dust dispersion from the mining face and for ensuring safe level of dust concentration in the mine tunnel for safety of the *** methods used include:application of blowing and exhaust fans,application of brattice and combination of *** results suggest that among the examined methods,implementation of appropriately located brattice to direct the flow from the main shaft to the mining face is the most effective method to direct dust particles away from the mining face.

关键词： Dust dispersion Modeling Undergrouand mine Ventilation