Mechatronics Engineering
http://repository.dkut.ac.ke:8080/xmlui/handle/123456789/80
Mechatronics Engineering2024-03-28T16:40:34ZProcess Modelling of Geothermal Drilling System Using Digital Twin for Real-Time Monitoring and Control
http://repository.dkut.ac.ke:8080/xmlui/handle/123456789/4950
Process Modelling of Geothermal Drilling System Using Digital Twin for Real-Time Monitoring and Control
Osinde, Nahashon O.; Byiringiro, Jean B.; Gichane, Michael M.; Smajic, Hasan
Currently, Kenya supplies its energy demand predominantly through hydroelectric power, which fluctuates due to poor and unpredictable rainfall in particular years. Geothermal energy is proposed as a clean and reliable energy source in meeting Kenya’s increasing energy demand. During geothermal drilling operations, disruptions due to tool wear and breakages increases the cost of operation significantly. Some of these causes can be mitigated by real-time monitoring of the tool head during operations. This paper presents the design and implementation of a digital twin model of a drilling tool head, represented as a section of a mechatronic assembly system. The system was modelled in Siemens NX and programmed via the TIA portal using S7 1200 PLC. The digital model was programmed to exactly match the operations of the physical system using OPC (open platform communications) standards. These operations were verified through the motion study by simultaneous running of the assembly system and digital twin model. The study results substantiate that a digital twin model of a geothermal drilling operation can closely mimic the physical operation
2019-08-17T00:00:00ZRecent Developments in Laser Sources for Industrial Applications
http://repository.dkut.ac.ke:8080/xmlui/handle/123456789/1021
Recent Developments in Laser Sources for Industrial Applications
Alphonse Niyibizi; Kioni, Paul Ndirangu; Ikua, Benson G.
2014-05-01T00:00:00ZA numerical and experimental study of the structure of laminar triple flames propagating in mixing layers
http://repository.dkut.ac.ke:8080/xmlui/handle/123456789/1007
A numerical and experimental study of the structure of laminar triple flames propagating in mixing layers
Kioni, Paul Ndirangu; Mohy S. Mansour; Peter Terhoeven; Tobias Plessing; Norbert Peters
A lifted laminar axisymmetric diffusion flame is stabilized in the downstream region of a diluted methane jet that is surrounded by a lean methane-air co-flow and an outer co-flow of air. The flame shows a distinct triple flame structure in the stabilization region. It is investigated experimentally by PIV for the velocity field, OH-LIPF imaging, C2Hx-LIF imaging, and a 1D-Raman technique for major species concentrations, combined with a Rayleigh technique for temperature. This is complemented by numerical simulations solving the two-dimensional axisymmetric Navier-Stokes equations in the zero Mach number limit on an adapted mesh, coupled with balance equations for temperature and species. A simplified model for molecular transport properties was used with constant, but non-unity, Lewis numbers for all species. Chemistry is represented by a ten-step reduced mechanism for methane oxidation, which was derived starting from a 61-step elementary mechanism that includes the C1 and C2 chains. The agreement between the measured and the predicted flow field is very satisfactory. Owing to gas expansion, the velocity decreases immediately ahead of the flame and increases strongly at the flame front. Further downstream acceleration due to buoyancy is dominant and is predicted accurately. There is a good agreement between measurements and computations for flame shape and flame length. The measured OH-LIPF image and the computed OH concentrations indicate that OH is concentrated in the vicinity of stoichiometric mixture. The results from a newly developed C2Hx-LIF method are also supported by calculations. While these measurements were only qualitative, the temperature and mole fractions of the major species could be measured quantitatively with the combined Raman-/Rayleigh technique along a line and were found to agree well with the numerical predictions. It is found that the structure is a triple flame and is influenced essentially by two external parameters: heat exchange between the branches and heat loss at the curved flame front near the triple point.
1994-05-01T00:00:00ZLaser material processing in crystalline silicon photovoltaics
http://repository.dkut.ac.ke:8080/xmlui/handle/123456789/1006
Laser material processing in crystalline silicon photovoltaics
Kioni, Paul Ndirangu; Alphonse Niyibizi; Bernard W. Ikua; P.K. Kihato
Lasers play a major part in the processing of the
numerous materials used in engineering and manufacturing. The
range of processes in which lasers are involved is ever increasing.
One of the areas in which laser has recently found application is in
energy systems. With the dwindling non-renewable sources of
energy such as fossil fuels and increasing demand of electricity, there
is increasing interest in addressing the energy problem through
development of systems for renewable energy alternatives such as
solar energy. Though solar energy is readily available and has no
adverse effects on environment such as pollution and greenhouse
effects, it has not been fully exploited due to a number of challenges.
Some of these challenges include high capital cost and the low
conversion efficiency. Therefore photovoltaic industry has taken
advantage of the benefits inherent in laser technology, namely
accuracy, cost-efficiency, and flexibility that are critical in
manufacturing today. This paper presents a review of the various
production and assembly methods employed in the manufacture of
solar panels where laser technology plays a predominant and the
types of lasers are preferred along the photovoltaic production chain
from the silicon raw material to the finished laminated solar modules.
2012-05-01T00:00:00Z