Research Articles

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Assessing the Performance of Liquid Waste Disposal Systems in West Africa: A Case Study in Ghana and Nigeria.
(Engineering Proceedings, 2022) Omani, J.; Acakpovi, A.
This research is an assessment of existing liquid waste disposal systems in West Africa and their performances over the years, using systems in Ghana and Nigeria as a case study. The main purpose of the study was to improve upon the sustainability of the systems, which according to earlier research activities, have been failing and resulting in health hazards. Ghana and Nigeria were selected because, from occurrences, especially in the West African sub-region, the two countries dictate the pace in contributions to the body of knowledge. Many portable liquid waste disposal systems were identified as part of the research process, as earlier researchers called for a paradigm shift from the practice of Europeanized systems that had not been successful in the entire sub-region. Many reasons have been attributed to the failures, and more worryingly, the systems continue to be operational despite their states of malfunctioning. Frequent power cuts and ineffective revenue generation contribute to numerous problems. West Africans have been enduring these occurrences for a long time with no solution in place. In a few instances, raw sewage is piped into a central biogas system for the future generation of electrical power; this system was found to be right on point because it was determined from the initial stages of development that by-products could be used to mitigate the high costs of maintenance. Another system that combines a biofil digester with its treated wastewater being channeled into a saturation pond was found to be a success because the outflow from the biofil was not meant to be channeled into main drains, as it did not wholly meet EPA approvals. The centralized sewage treatment systems have been functioning well in advanced countries; however, they are found to be ineffective in developing countries. The reasons included lack of availability for spare parts and coagulants, etc., which were normally imported. Additionally, when a larger community is targeted, revenue generation becomes a problem, thereby affecting return on investments (ROI) and operating and maintenance (O&M). None of the available central sewerage systems harvest by-products, making revenue generation a difficult task. The portable systems have been discussed in this research study, with examples and a record of performance over the years that could contribute to the body of knowledge in the field of sustainability for sewage treatment processes suitable for West Africa and for the whole of sub-Saharan Africa.
Impact of energy efficiency and conservation programs on the national grid in some selected households in Ghana.
(Energy Efficiency, 2022) Acakpovi, A.; Botwe-Ohenewaa, G.; Sackey, D. M.
This study evaluates the effect of energy efficiency and conservation on the Ghana National Grid. The motivation of this research study derives from the overwhelming lack of energy efficiency and conservation practices by consumers in Ghana while the existing generation continues to deplete with the increasing population and their growing energy needs. A survey was conducted on existing generation plants to assess their capacities and average power contributed to the national grid over a 6-month period. Energy efficiency and conservation awareness questionnaires was also administered to selected consumers to test their knowledge in energy efficiency and conservation. An energy audit and demand management program was established and implemented for a set of households, which were later audited, after a 3-month period to ascertain improvements in their energy consumption pattern. The study revealed that the implementation of energy efficiency and conservation measures led to a maximal reduction of energy consumed by 5.14% which is highly significant and subsequently led to positive economic and environmental implications. The study also found out that most of the respondents are unaware of energy efficiency and conservation measures; they make abusive use of non-efficient electrical appliances and do not implement any energy efficiency and conservation measures. The study recommended the development of policies and strategies to conduct mass education, to ensure the implementation of energy efficiency and conservation measures, and also to encourage the use of energy-efficient appliances. Successful implementation of the proposed recommendations contribute significantly to meeting the energy challenge in developing countries and subsequently sustain business while alleviating poverty.
Maximum Power Point Tracking in Power System Control Using Reservoir Computing.
(Frontiers in Energy Research, 2022) Seddoh, M. A.; Sackey, D. M.; Acakpovi, A.; Owusu-Manu, D. G.; Sowah, R. A.
This article deals with an innovative approach to maximum power point tracking (MPPT) in power systems using the reservoir computing (RC) technique. Even though extensive studies have been conducted on MPPT to improve solar PV systems efficiency, there is still considerable room for improvement. The methodology consisted in modeling and programming with MATLAB software, the reservoir computing paradigm, which is a form of recurrent neural network. The performances of the RC algorithm were compared to two well-known methods of maximum power point tracking: perturbed and observed (P&O) and artificial neural networks (ANN). Power, voltage, current, and temperature characteristics were assessed, plotted, and compared. It was established that the RC-MPPT provided better performances than P&O-MPPT and ANN-MPPT from the perspective of training and testing MSE, rapid convergence, and accuracy of tracking. These findings suggest the need for rapid implementation of the proposed RC-MPPT algorithm on microcontroller chips for the widespread use and adoption globally
Forecast of impacts of climate change on hydropower potential of Ouémé River at the 2040’s horizon in Benin
(International Journal of Energy and Power Engineering, 2018) Nounangnonhou, T. C.; Fifatin, F. X. N.; Aza-Gnandji, R. M.; Acakpovi, A.; Sanya, E. A.
Water is the most essential element for hydropower energy production. However, it has been well established that climate change will negatively globally impact water resources and in Sub-Saharan Africa particularly. It is therefore important to take this into account when assessing the potential hydropower energy of rivers to avoid overestimating their production’s capacity. This article firstly deals with the impacts of climate change on the forecast of potential hydropower energy of the Ouémé River Basin by 2040 and secondly develops the best equations for its exploitation. The data collected on three representative sites of the Ouémé River Basin (Bétérou, Savè, Kétou) from 1989 to 2016 and those derived from simulation of its flows from 2017 to 2040 by the Rural Engineering model (GR2M), made it possible to determine, first the monthly mean flow and, with the classified flow rate method, then evaluate the associated operating times. Using the obtained two parameters (mean flow-rate, production’s time), the hydropower energy was estimated as well, for period of 1989 to 2016, as for that of 2017 to 2040, and this in each of the retained three sites. The results show that the exploitable nominal flow-rates by hydro-electrical equipment set that can be installed are respectively 50 m3/s at Bétérou, 90 m3/s at Savè and 145 m3/s at Kétou. These results showed Kétou as the best site capable of hosting the largest hydropower energy plant on the Ouémé river basin. In Bétérou and Savè, the two-machines option (respectively 25 m3/s and 45 m3/s) is the most profitable, in terms of potential hydropower energy and its production duration, whereas in Kétou, the three-machines option of 50 m3/s each is the best.
Modelling and prediction of Ouémé (Bénin) river flows by 2040 based on GR2M approach
(LARHYSS Journal, 2018) Nounangnonhou, T. C.; Fifatin, F.; Lokonon, B. E.; Acakpovi, A.; Sanya, E. A.
The study described in this paper has consisted of simulating the real future behaviour of the Ouémé river basin's water flow by 2040. The approach of the Rural Engineering model, with two variables, at a monthly time step named GR2M has been adopted owing to its robustness. This model is an indispensable tool for studying the evolution of water resources in the medium and long term. For our approach, the projected data, from 2016 to 2040, were generated using the Auto-Regressive Integrated Moving Average model. Observed data were then used for the calibration and the validation of the GR2M model. The results obtained showed that the GR2M model is a very satisfactory tool for simulating the transformation of rainfall data into flows on the one hand and an impact of future climate change resulting in a decrease in annual average flows between 11.90% and 46.37% by 2040 on the other hand. The quality parameters revealed very interesting values obtained from the model on the three representative sites of the Ouémé basin with Nash-Sutcliffe more than 70% and determination coefficient more than 0.75.
Harmonics of CF and LED lamps-maximum penetration perspective on power quality in distribution systems.
(Jurnal Nasional Teknik Elektro, 2020) Effah, F. B.; Gasu, P.; Okyere, P.; Acakpovi, A.
Global energy saving efforts have led to replacement of incandescent lamps with energy-efficient ones like light-emitting diode (LED) and compact fluorescent lamps (CFLs). These lamps, being non-linear loads, have the potential of injecting harmonics into distribution networks. In this paper, harmonics injection of common CFL and LED lamps at a facility point of common coupling is investigated. To gain insight into large scale penetration effects on power quality, field measurement results of popular lamps used in Ghana were replicated in MATLAB/Simulink through simulation. The field results showed that LED lamps exhibit more harmonics compared to CFL lamps. Maximum possible loading on a 100-kVA, 11kV/0.433kV distribution transformer was found to be 24.02% for CFL, 27.14% for LED, and 40.91% for a mixture of the two lamps, respectively, in order not to violate IEEE 519-2014 standard. The influence of other common loads such as ceiling fans on the lamps’ harmonics were assessed in the field measurement. The use of ceiling fans with the lamps in the facility reduced the harmonics and improved the power factor of the facility. Since the lamps exist in residential and commercial facilities with other loads, more penetration of energy-saving lamps in the distribution system will have little influence on power quality.
Entrepreneurship and the Need for Sustainable new technologies in power generation
(Energy and Power Engineering, 2020) Bani, S.; Abbey, S.; Quaynor, N.; Essel, E. A.
The increase of micro and nano devices has led to the miniaturization and multi-functionalization of micro-mechanical, communication, imaging, sensing, chemical analytical and biomedical devices. The devices so mentioned above need power sources that are portable, have short charging time, longevity, high energy density and are environmentally friendly. Chemical batteries hitherto used to be the major power source for these devices but have a drawback of having low energy density. The energy density of the most improved lithium-ion battery was in the region of 0.2 kWh/kg. Micro-combustor is one of the most important components of the micro thermophotovoltaic (MTPV) conversion device. This work used numerical simulation to investigate the effect of Micro pin fin arrays on combustion. Using a micro combustor with micro pin-fin arrays inserted, it was observed the fins widened the region of combustion and extended the blow-off limit in the combustor. The fins exerted great influence on combustion as flow rate increased and thus improved the temperature distribution of the wall. The combustor with fins possessed higher heat flux in comparison with combustor without fins. There was combustion stability at inlet velocity of 4 m/s making the micro pin-fin array configuration ideal for MTPV application. The results obtained will be useful in designing a MTPV.
Original framework for optimizing hybrid energy supply.
(Journal of Energy, 2016) Acakpovi, A.
This paper proposes an original framework for optimizing hybrid energy systems. The recent growth of hybrid energy systems in remote areas across the world added to the increasing cost of renewable energy has triggered the inevitable development of hybrid energy systems. Hybrid energy systems always pose a problem of optimization of cost which has been approached with different perspectives in the recent past. This paper proposes a framework to guide the techniques of optimizing hybrid energy systems in general. The proposed framework comprises four stages including identification of input variables for energy generation, establishment of models of energy generation by individual sources, development of artificial intelligence, and finally summation of selected sources. A case study of a solar, wind, and hydro hybrid system was undertaken with a linear programming approach. Substantial results were obtained with regard to how load requests were constantly satisfied while minimizing the cost of electricity. The developed framework gained its originality from the fact that it has included models of individual sources of energy that even make the optimization problem more complex. This paper also has impacts on the development of policies which will encourage the integration and development of renewable energies.
An investigation of health and safety measures in a hydroelectric power plant.
(Safety and Health at Work, 2016) Acakpovi, A.; Dzamikumah, L
Background: Occupational risk management is known as a catalyst in generating superior returns for all stakeholders on a sustainable basis. A number of companies in Ghana implemented health and safety measures adopted from international companies to ensure the safety of their employees. However, there exist great threats to employees' safety in these companies. The purpose of this paper is to investigate the level of compliance of Occupational Health and Safety management systems and standards set by international and local legislation in power producing companies in Ghana. Methods: The methodology is conducted by administering questionnaires and in-depth interviews as measuring instruments. A random sampling technique was applied to 60 respondents; only 50 respondents returned their responses. The questionnaire was developed from a literature review and contained questions and items relevant to the initial research problem. A factor analysis was also carried out to investigate the influence of some variables on safety in general. Results: Results showed that the significant factors that influence the safety of employees at the hydroelectric power plant stations are: lack of training and supervision, non-observance of safe work procedures, lack of management commitment, and lack of periodical check on machine operations. The study pointed out the safety loopholes and therefore helped improve the health and safety measures of employees in the selected company by providing effective recommendations. Conclusion: The implementation of the proposed recommendations in this paper, would lead to the prevention of work-related injuries and illnesses of employees as well as property damage and incidents in hydroelectric power plants. The recommendations may equally be considered as benchmark for the Safety and Health Management System with international standards.
Performance analysis of particle swarm optimization approach for optimizing electricity cost from a hybrid solar, wind and hydropower plant
(International Journal of Renewable Energy Research (IJRER), 2016) Acakpovi, A.
This paper deals with the cost optimization of a hybrid solar, wind and hydropower plant using a Particle Swarm Optimization (PSO) approach. PSO is a technique that belongs to Swarm intelligence, an artificial intelligence (AI) technique, known as a Meta-heuristic optimization solver, mostly used in Biology. With the consideration of solar, wind and hydro hybrid system which has become extremely relevant for developing countries, and also the existence of a wide list of constraints, the adoption of PSO technique cannot be avoided. On the other hand, a linear optimization approach was used with Matlab software to solve the same problem. Both techniques were applied to secondary data collected from RetScreen Plus software for the location Accra and results were extracted in terms of distribution of supply by individual sources and cost of hybrid system electricity. Results show in general, an improvement of hybrid system cost of electricity. A histogram was used to show the distribution of supply for the particular load and the equivalent cost of hybrid system that corresponds to it. A khi-sqaure test was run to compare the two series of data obtained from the two approaches adopted. The Khi-square test show high similarity confirming the reliability of the PSO approach which on the other hand presents the advantage of scalability over a wider range of sources with multiple constraints.
Experimental investigation on the combustion characteristics of premixed CH4/O2 flame in a micro plate channel.
(Energy Procedia, 2017) Zha, Z.; Pan, J.; Yang, W.; Lu, Q.; Bani, S.; Shao, X.
The combustion characteristics of premixed rich CH4/O2 in micro channel was investigated experimentally via the visual micro-scale combustion test bench. The flammability limits, flame behaviors, stability limits and flame propagation speed were researched by changing the combustor sizes and inlet flow rates. The results show that there are three flame behaviors observed in the experiment, respectively external flame at the exit, stable flame in the channel, flame with repetitive extinction and ignition (FREI). Stable combustion zone increases with the increase of CH4 inlet flow rate. But the stability of the flame at high velocity may not be increased when the inlet flow rate is increased. The flammability limit was greater when the channel height was larger. Meanwhile, the increasing height and the decreasing length of the channel were also beneficial to stability limits in the channel with a certain range of equivalence ratios of 1.25 - 1.80. This experimental study on the combustion characteristics of premixed rich CH4/O2 in micro planar channels provides support for micro combustion in the future.
Interaction between heterogeneous and homogeneous reaction of premixed hydrogen–air mixture in a planar catalytic micro-combustor.
(International Journal of Hydrogen Energy, 2017)
Hetero-/homogeneous combustion of hydrogen–air mixture in a platinum-coated micro channel was studied by means of three-dimensional (3D) Computational Fluid Dynamics (CFD) model using detailed reaction mechanisms for homogeneous (gas phase) and heterogeneous (catalytic) reactions. The influence of heterogeneous reaction on homogeneous reaction was obtained by discussing the hetero-/homogeneous reaction characteristics, the process and competitiveness of heterogeneous reaction. Intense depletion of fuel and product formation near the inlet has shown that fuel absorption reaction was predominant whiles there was no homogeneous reaction. The free radicals from homogeneous reaction near the catalytic surface were drained, resulting in the interruption of chain reaction. The desorbed product as the third-body promoted the chain terminating reaction to deactivate free radical. The competitiveness value of heterogeneous reaction for capturing fuel was 14.85%, indicating a weak reaction intensity in the catalytic combustor. The heterogeneous reaction presented an inhibition effect on homogeneous reaction but greatly enhanced the combustion efficiency in the micro channel.
Hetero-/homogeneous combustion characteristics of premixed hydrogen-air mixture in a planar micro-reactor with catalyst segmentation
(Chemical Engineering Science, 2017) Pan, J.; Lu, Q.; Bani, S.; Tang, A.; Yang, W.; Shao, X.
Numerical simulation of stoichiometric hydrogen-air premixed flame in a platinum-coated micro channel was performed to investigate hetero-/homogeneous combustion characteristics. An elliptical two-dimensional (2D) Computational Fluid Dynamics (CFD) model with detailed reaction mechanisms for homogeneous (gas phase) and heterogeneous (catalytic) reactions was adopted. The hetero-/homogeneous reaction characteristics with different inlet flow velocities and flame speeds were used to evaluate the effect of heterogeneous reaction on homogeneous reaction in the combustor with 2 mm length of catalyst segmentation. The effect of heat generation of the heterogeneous reaction was also analyzed. The numerical results indicated that the highest temperature in the catalytic combustor was lower than that in the combustor without catalyst. In the presence of heterogeneous reaction, the species (OH) concentration near the catalytic surface decreased significantly due to the dominated heterogeneous reaction at that region. The homogeneous ignition distance increased with increasing inlet flow velocity. The heat transfer from the catalytic surface to the gaseous mixture in the catalytic zone exhibited a high intensity under the large flow velocity, and the preheated incoming flow improved the heterogeneous reaction to inhibit the homogeneous reaction. The decreased flame speed in the catalytic combustor further demonstrated that the homogeneous reaction was suppressed by the heterogeneous reaction.
Experimental study on premixed methane-air catalytic combustion in rectangular micro channel
(Applied Thermal Engineering,, 2017)
The catalytic combustion process of pre-mixed methane-air in a rectangular micro channel was studied experimentally. Infrared thermal imager and flue gas analyzer were used to measure the temperature distribution of the outer wall and main components of exhaust gas respectively. Flammability limits of premixed methane-air in catalytic and non-catalytic micro channel were obtained by changing flow rates of methane, and the effects of equivalence ratio, inlet velocity and channel height on combustion characteristics were analyzed. Results showed that the flammability limits improved significantly when platinum was added into the micro channel. The highest centerline temperature of the outer wall was obtained at an equivalent ratio of 0.9 at the same inlet velocity with or without catalyst in the micro channel. Addition of catalyst in the channel not only gave a uniform temperature distribution on the outer wall of the channel but also improved methane conversion. With the increase of inlet velocity, the centerline temperature of the outer wall increased and the highest points of the temperature shifted to downstream of the channel gradually. Combustion intensity in the channel increased with the increase of channel height at the same inlet velocity.
The influence of injection strategy on mixture formation and combustion process in a direct injection natural gas rotary engine.
(Applied Energy, 2017) Fan, B.; Pan, J.; Yang, W.; Chen, W.; Bani, S.
The application of direct injection (DI) technology is considered as an effective way to improve the performance of the rotary engine. This work seeks to numerically dissect the influence of injection strategy on mixture formation and combustion process in a DI natural gas rotary engine. A 3D dynamic simulation model established in our previous work was used to acquire some critical information which was difficult to obtain through experimental investigations. These were the flow field, the fuel distribution, the temperature field and some intermediate concentration fields in the combustion chamber. Simulation results showed that for mixture formation, the motion mechanism of the fuel varies with the injection position. The mass of fuel located at the back of the combustion chamber for injection nozzles A, B and C, was determined by the intensity of vortex I, the coupling function between the value of the impact angle and the intensity of vortex I, and the value of the impact angle respectively. In addition, with retarded injection timing, the accumulation area of fuel for all injection nozzle positions moved from the back to the front of the combustion chamber at ignition timing. For combustion process, the overall combustion rate for the injection strategy (case A4) whose nozzle was 50 mm apart along the engine major axis and whose injection timing was 360°CA (BTDC), was the fastest. Compared with the out-cylinder premixed gas-filling method (case premix method), the improved combustion rate of case A4 had a 29.7% increase in peak pressure, but also a certain increase in NO emissions.
Optimum design of a stand-alone hybrid power system with demand-side management.
(Procedia Manufacturing, 2017) Michael, M. B.; Acakpovi, A.
Hybridising renewable energy sources improves the reliability of renewable energy systems for stand-alone applications. However, the high system cost is one of the setbacks that contribute to the slow growth of renewable energy development. The system cost can be reduced by optimal system design. This paper presents hybrid system design strategies that minimize the system capital cost. The design concept considers integration of demand-side management (DSM) strategy in the system design process. In this strategy, the residential load is divided into three categories and prioritized two of them. This reduces the peak load, in effect reduces the system design capacity. A traditional design method was used to design a hybrid system to meet a specific daily load profile of a typical 3-bedroom residential facility in Tema, Ghana. The system capacity, system capital cost, net present cost, capacity shortage and excess generation of the system were considered as hypothesis. The algorithm of the proposed design strategy was used to design an optimal system for the same daily load profile. Upon comparison of the two systems, the following observations were made; the system capacity reduced from 8.4 kW to 4.3 kW, the initial cost and the net present cost of the optimal system reduced by 48% and 41.5% respectively, system capacity shortage was slightly improved from 9.5% to 8.8%. The costs of energy (COE) improved from 0.793 kWh to 0.742 kWh, 6.4% reduction. The resualmost half which significantly reduced the system initial cost by 41.5 percent.lts indicate that, the proposed design method reduces the system capacity by
Combined effect of injection timing and injection angle on mixture formation and combustion process in a direct injection (DI) natural gas rotary engine
(Energy, 2017) Fan, B.; Pan, J.; Yang, W.; Pan, Z.; Bani, S.; Chen, W.; He, R.
The application of direct injection (DI) technology is considered as a key solution to the problems of combustion efficiency and emissions on the rotary engine. This work aimed to numerically study the combined effect of injection timing (IT) and injection angle (IA) on mixture formation and combustion process in the 3D flow field of a DI natural gas rotary engine. On the basis of the 3D dynamic simulation model which was established in our previous work [29, 30], some critical information was obtained which was difficult to acquire through experiment. Simulation results showed that to satisfy the ideal fuel distribution for high combustion rate, a small IA should be used when the IT was at the early stages of intake stroke, and a big IA should be used when the IT was at the early stages of compression stroke. However, when the IT was at the middle and later stages of intake stroke, the IA which could satisfy the ideal fuel distribution, was difficult to determine with the changed IT in the middle and later stage of intake stroke. For the above reason, the middle and late stage of intake stroke was not recommended as injection timing in engineering application.
Industrial applications of clay materials from Ghana-A review.
(Oriental Journal of Chemistry, 2018) Asamoah, R. B.; Nyankson, E.; Annan, E.; Agyei-Tuffour, B.; Efavi, J. K.; Kan-Dapaah, K.; Yaya, A.
Clay minerals are phyllosilicate groups naturally found in soils in all parts of the world. They have proven to be among the most essential industrial minerals because of their unique physicochemical properties and versatile applications within a wide range of fields including ceramics, construction, and environmental remediation, biomedical as well as cosmetics. Clay minerals are also primary to the production of other materials such as composite for secondary applications. In Ghana, clay mineral deposits are commonly found in several areas including soil horizons as well as geothermal fields and volcanic deposits, and are formed under certain geological conditions. This review seeks to explore the geographical occurrence and discusses the current uses of various local clay materials in Ghana in order to highlight opportunities for the utilization of these materials for other applications
The characteristics of pure heterogeneous reaction for H2/Air mixture in the micro-combustors with different thermophysical properties.
(Applied Thermal Engineering, 2018) Zhang, Y.; Pan, J.; Lu, Z.; Tang, A.; Zhu, Y.; Bani, S.
This paper investigated the characteristics of pure heterogeneous reaction for H2/Air mixture under different wall thermophysical conditions namely; thermal conductivity, convective heat transfer and thermal capacity. The phenomena of pure heterogeneous reaction were observed by OH Planar Laser induced Fluorescence (OH-PLIF) to determine the working conditions. (3D)-models were built to numerically study the effects of different wall thermophysical conditions. The results show that lower thermal conductivity and convective heat transfer coefficient is beneficial to enhancing heterogeneous reaction and improve conversion rate of H2 as less heat is dissipated. The greater thermal capacity has beneficial impact on the reaction stability when the boundary condition changes, but no effect under the steady state. The performance of thermal conduction and convection were comprehensively considered to study the influence and proportion of each on the heterogeneous reaction. Higher thermal resistance can improve the reaction efficiency, reaction stability and reduce application cost. The influence of thermal conduction is greater than that of convective heat transfer.
The effect of embedded high thermal conductivity material on combustion performance of catalytic micro combustor.
(Energy Conversion and Management, 2018) Zhang, Y.; Pan, J.; Zhu, Y.; Bani, S.; Lu, Q.; Zhu, J.; Ren, H.
A novel micro combustor embedded with high thermal conductivity material has been proposed for micro-thermophotovoltaic system application. The effect of the materials, which is graphite and nickel with widths 1 mm and 3 mm on the thermal and radiant performance of the new micro combustor, was experimentally and numerically investigated. It was found that high and uniform temperature distribution along the walls of the combustor was obtained by embedding graphite with width of 1 mm because of the enhanced heat transfer, which is desirable for the micro-thermophotovoltaic system. The available radiation energy increased from 4.6 W for the conventional combustor to 5.2 W for the novel combustor when the inlet velocity was 1.0 m/s and the hydrogen/oxygen equivalence ratio was 0.5 under the experimental conditions. The available radiation efficiency increased from 8.9% to 9.8% and the effect of the embedded material could be enhanced by increasing the chemical energy input. Based on the combustor and fuel in this study, the conditions for good thermal performance are graphite with width of 1 mm, inlet velocity of 1.0 m/s and 0.5 equivalence ratio of hydrogen/oxygen by considering the reliability and durability of the combustor.

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