Temperature In Combustion Chamber Research Articles

Efficient Thermal Integration Model based on a Biogas-fired Gas Turbine Cycle (GTC) for Electricity and Desalination Applications; Thermo-Economic and GA-based Optimization

As the global energy demand continues to rise, there is an urgent need to improve the efficiency and sustainability of power generation systems. This study integrated a modified supercritical carbon dioxide (S-CO2) and multi-effect desalination (MED) units to recover residual heat from a gas turbine cycle (GTC) in two stages, significantly enhancing electricity production while reducing the environmental footprint of the GTC. The significance of this study lies in its comprehensive approach, combining thermodynamic, environmental, and thermoeconomic analyses alongside thorough sensitivity evaluations. A triple optimization framework was implemented to optimize the system's performance, focusing on key metrics such as exergy efficiency, CO2 reduction rates, and levelized energy cost, utilizing the NSGA-II and the TOPSIS decision-making method in MATLAB software. Economic viability was assessed through a net present value (NPV) analysis, demonstrating substantial profitability. Finally, a comparison study of the devised system CO2 emissions rate was performed for different renewable energy sources. A specific application of the devised system is its capacity to generate 1.415 m³/h of distilled water while generating 1441 kW of electricity. Sensitivity analysis identified the combustion chamber temperature as the most critical design parameter, with a sensitivity index of 0.328. The optimum economic indicators showed marked improvement, with the NPV increasing from 2.371 M$ to 10.75 M$ and the payback period decreasing from 13.28 years to 7.18 years.

Liquid Rocket Engine Performance Characterization Using Computational Modeling: Preliminary Analysis and Validation

The need to refuel future missions to Mars and the Moon via in situ resource utilization (ISRU) requires the development of LOX/LCH4 engines, which are complex and expensive to develop and improve. This paper discusses how the use of digital engineering—specifically physics-based modeling (PBM)—can aid in developing, testing, and validating a LOX/LCH4 engine. The model, which focuses on propulsion performance and heat transfer through the engine walls, was created using Siemens’ STAR-CCM+ CFD tool. Key features of the model include Eulerian multiphase physics (EMP), complex chemistry (CC) using the eddy dissipation concept (EDC), and segregated solid energy (SSE) for heat transfer. A comparison between the complete GRI 3.0 and Lu’s reduced combustion mechanisms was performed, with Lu’s mechanism being chosen for its cost-effectiveness and similar output to the GRI mechanism. The model’s geometry represents 1/8th of the engine’s volume, with a symmetric rotational boundary. The performance of this engine was investigated using NASA’s chemical equilibrium analysis (CEA) and STAR-CCM+ simulations, focusing on thrust levels of 125 lbf and 500 lbf. Discrepancies between theoretical predictions and simulations ranged from 1.4% to 28.5%, largely due to differences in modeling assumptions. While NASA CEA has a zero-dimensional, steady-state approach based on idealized conditions, STAR-CCM+ accounts for real-world factors such as multiphase flow, turbulence, and heat loss. For the 125 lbf case, a 9.2% deviation in combustion chamber temperature and a 15.0% difference in thrust were noted, with simulations yielding 113.48 lbf compared to the CEA’s 133.52 lbf. In the 500 lbf case, thrust reached 488 lbf, showing a 2.4% deviation from the design target and an 8.6% increase over CEA predictions. Temperature and pressure deviations were also observed, with the highest engine wall temperature at the nozzle throat. Monte Carlo simulations revealed that substituting LNG for LCH4 affects combustion dynamics. The findings emphasize the need for advanced modeling approaches to enhance the prediction accuracy of rocket engine performance, aiding in the development of digital twins for the CROME.

Improving used Lubricant Oil Burner Performance: Effect of Swirled Flow of Internally Distributor Type on the Combustion and Flue Gas Temperature and Emission

This study aimed to experimentally investigate the combustion characteristics of used lubricant oil (ULO). A simple cylindrical burner of the natural draft vaporizing type, equipped with an internal air distributor, was designed and fabricated to achieve this objective. The burner’s efficiency was evaluated based on combustion temperature, flue gas temperature, and concentration levels. The key feature of this burner lies in the swirled flow of air combustion and ULO vapor within the combustion chamber, facilitated by the swirled flow air distributor type. Various air-fuel ratios (ϕ), ranging from 0.5 to 4, were considered in characterizing the burner’s performance. The results revealed increased combustion and flue gas temperatures in the radial airflow types. The highest temperatures achieved using the radial flow type are 930 oC and 410 oC for combustion and exhaust gas temperature, respectively. In contrast, the combustion chamber and exhaust gas temperatures are 980 oC and 465 oC for the swirled flow type, respectively. It was found that there is a decrease in the emission of CO and CO2 by volume under optimum conditions. This decrement was attributed to the swirled flow effects, which promoted a better mixture of air combustion and ULO vapor during combustion.

Analysis of cooling effects and measurement errors in water-cooled thermocouples for total temperature measurement in aviation engine combustion chambers

Accurate measurement of the total temperature in the main combustion chamber of an aviation engine is crucial for assessing engine performance. However, a significant challenge exists in balancing the heat transfer errors caused by the necessary cooling of the measuring device with measurement precision. The research employs a combination of numerical simulations and experimental methods to investigate this issue. The numerical simulations utilized the Reynolds-averaged Navier Stokes (RANS) coupled with a conjugate heat transfer approach to study the primary flow characteristics and heat transfer properties within the combustion chamber and the probe body. The experiments were conducted in a heat-calibration wind tunnel, validating the results of the numerical simulations. The results show that by implementing water cooling, the probe's body temperature can be reduced from 1200 °C in high-temperature conditions to 400 °C, with localized temperature imbalances still present in the edge areas of the probe. Tracing the cooling water path reveals that the vertical bends in the internal channels lead to an increase in localized pressure loss of the cooling water. The study quantitatively analyzes measurement errors caused by three heat transfer modes: radiation, convection, and conduction. In low-load conditions of the combustion chamber, heat conduction plays a dominant role, with measurement errors due to conduction reaching up to 70 % of the total measurement error. Radiation further increases the temperature measurement errors of the thermocouple's junctions near the chamber wall. As the combustion chamber temperature increases, entering high-load conditions, the cooling effect of water becomes limited, reducing conduction errors and increasing radiation errors. In these conditions, radiation errors constitute 60–70 % of the total measurement error. It suggests the importance of considering temperature corrections when using water-cooled temperature measurement devices. The research reveals several crucial insights regarding the performance and limitations of water-cooled thermocouples.

Experimental investigation of the effect of air/fuel ratio change on JP8 swirl flame characteristics with image processing methods

In this study, the stable combustion ranges and emission values of JP8 fuel, which is used in military aviation, were tested and optimum conditions were determined. The AFR (Air/Fuel Ratio) of the JP8 flame was increased experimentally at constant thermal power in a gas turbine combustion chamber. In the study, AFR were tested as 30/1, 33/1, 36/1, 39/1 and 42/1. A generator with 0.4 swirl number is placed at the burner outlet. Under these conditions, the effect of external acoustic enforcement frequencies on dynamic instabilities at different AFR was investigated. Flame length and thickness data were extracted from the images obtained from the image processing technique. The effect of AFR change on the combustion chamber temperature was examined and pollutant emissions were measured. The results showed that the most stable flame appeared in AFR 33/1 case at 155 and 300 Hz resonance frequencies under acoustic enforcements. Additionally, when the AFR was increased to 42/1, flame instability increased at all frequency values. Moreover, it has been determined that the most optimum mixture in terms of combustion chamber exit temperature and CO emissions is AFR 33/1. There was an increase in NOX emissions by up to 39/1 with the increase in AFR.

Characteristics of temperature uniformity system in multi-tier drying equipment with sharp turning technology

Drying is a process of heat and mass transfer that occurs on the surface and within the material to be dried. It helps reduce the internal moisture of the material, inhibiting the growth, damage, and chemical changes of microorganisms during storage, thus extending the shelf life of dry materials and improving the quality of raw materials. This study aims to test multi-level drying equipment using combustion heat with a square shape and racks inside it used as the drying space for the material. The raw material was placed on racks made of perforated metal. This research started from designing the drying equipment system, fabricating and testing system. The drying system was tested using fish and cocoa beans as sample materials. The tested equipment system included temperature distribution in the combustion chamber, distribution system of hot combustion gases through sharp turning technology, uniform temperature distribution in the drying chamber with 8 levels of racks, each capable of holding a load of 10 kg, and testing of the chimney system. The research findings concluded that to maintain a drying chamber temperature of 90⁰C, an average combustion chamber temperature of 339⁰C was required. The average combustion chamber temperature needed to maintain a drying chamber temperature of 80⁰C was 290⁰C. For a drying chamber temperature of 70⁰C, an average combustion chamber temperature of 314⁰C was required. The temperature distribution inside the drying chamber moves horizontally, indicating that the temperature distribution in the drying chamber was uniform for each drying rack.

Evaluation of selected combustion parameters in a compression-ignition engine powered by hydrogenated vegetable oil (HVO)

The article carries out a detailed analysis and evaluation of indicators related to the combustion process (pressure and temperature in the engine combustion chamber, heat release rate, heat release fraction) in a JCB 444 TA4i compression-ignition engine fuelled with diesel and hydrogenated vegetable oil (HVO). During the empirical tests, the operation of the exhaust gas recirculation (EGR) system was stopped and no other changes were made to the engine settings (factory settings were used). In the first stage, the empirical tests were carried out at speed characteristics on an engine dynamometer. Then, an experiment was carried out at the engine crankshaft speed corresponding to the maximum torque - which consisted of determining the indicators related to the combustion process at a constant mass flow of fuel: diesel and HVO fuel. This provided information on the effect of hydrogenated vegetable oil on the combustion process in relation to the diesel engine feed. The conclusions drawn from the empirical study can be used to develop guidelines to change the operating map of a compression-ignition engine when it is fed with hydrogenated vegetable oil.

Experimental Investigation on Oxy-Hydrogen Gas Flame Injecting Coal Powder Gasification and Combustion

Hydrogen energy is an important carrier for energy terminals to achieve green and low-carbon transformation. Hydrogen, as a carbon-free fuel, has great research and development value in the field of thermal power generation. This article proposes a solution for the stable combustion of coal powder using Oxy-hydrogen Gas ignition technology. An Oxy-hydrogen Gas flame injection coal powder combustion testing device was constructed to experimentally study the temperature distribution in the combustion chamber under Oxy-hydrogen Gas ignition technology, with primary air coal powder concentrations of 0.27, 0.32, and 0.36 (kg coal powder/kg air), as well as the concentration changes of volatile CO emissions during the ignition of coal powder using both Oxy-hydrogen Gas and CH4 flames. The sensitivity of the NO generation during coal gasification combustion under the Oxy-hydrogen Gas ignition was simulated and analyzed. The results show that at a coal powder concentration of 0.32 (kg coal/kg air) and an Oxy-hydrogen Gas flow rate of 2.1 L/min, the combustion effect of coal powder is the best, and the highest combustion chamber temperature can reach 1156 K; when the concentration of coal powder varies within a range from 0.32 to 0.27, the combustion chamber temperature can be maintained at around 850K, achieving stable combustion conditions for coal powder. The only product generated by the Oxy-hydrogen Gas combustion is high-temperature water vapor, which helps the rapid gasification of coal powder and releases a large amount of volatile CO, which is beneficial for the ignition and stable combustion of coal powder.

Experimental study on MILD combustion of methane under non-preheated condition in a swirl combustion furnace

In this paper, a swirl combustion furnace is designed and manufactured to realize MILD combustion. The influence of swirling air proportion, equivalence ratio and thermal power on MILD combustion are studied. The results reveal that the combustion chamber temperature is highest and the NO and CO emissions are lowest when the proportion of swirling air is 100%. Additionally, an appropriate equivalence ratio increases the combustion chamber temperature while reducing the NO and CO emissions during MILD combustion. Furthermore, CO emissions reach their minimum at a specific thermal power, while the temperature and NO emissions increase with thermal power. Overall, MILD combustion exhibits high stability under all experimental conditions, with NO emissions consistently below 30 ppm. Indeed, the findings underscore that the swirl combustion furnace is capable of achieving MILD combustion with superior combustion performance. This highlights the considerable potential of the combustion furnace for various applications, especially in areas where efficient and clean combustion is paramount.

Building a research model for the combustion process of fuel in a constant volume combustion chamber

ABSTRACT Blending biodiesel at different ratios leads to fluctuations in properties such as oxygen content, cetane number, speed, density, and calorific value, affecting performance and emissions. Therefore, studying the combustion process of biodiesel is necessary. This study describes the construction of a CVCC (Constant volume combustion chamber) model to study the fuel combustion process and the impact of temperature on the characteristic parameters of the combustion process. Fuels used for simulations included diesel fuel and B10 biodiesel derived from palm oil. The calculated results from the model are compared with experimental data to verify, analyse, and evaluate the combustion process in CVCC. Analysis of the influence of combustion chamber temperature shows that increasing the temperature from 300K to 450K leads to a decrease in the mixing time of the mixture, a decrease in the spray length, an increase in the fuel evaporation rate, and the combustion process occurs. Faster, the peak pressure appears earlier and higher, and the heat transfer rate is faster. Pressure increases faster during the delayed combustion phase. At the same time, increasing the oxygen concentration from 10% to 20% also leads to an increase in pressure rate, reaching an earlier peak, and the combustion process occurs faster.

Experimental Transient Process Analysis of Micro-Turbojet Aviation Engines: Comparing the Effects of Diesel and Kerosene Fuels at Different Ambient Temperatures

In this paper, we investigate the impact of diesel and kerosene on the transient processes occurring in a micro-turbojet aviation engine. The experiments were conducted under two distinct ambient temperature conditions, 0 and 20 °C. Specifically, we analyzed the starting phase of the micro-engine while operating with kerosene and diesel at both ambient temperature settings. Comparative graphs were generated, and the starting time was meticulously examined. Subsequently, we constructed performance maps for the engine using both fuels and across the two ambient temperature scenarios. We then executed a transient process, comprising sudden acceleration and deceleration, under the aforementioned ambient temperature conditions and with both fuels. The fluctuations in temperature within the combustion chamber, thrust force, and fuel consumption are presented for both rapid acceleration and deceleration events. Furthermore, we conducted comparisons between the thrust force, fuel flow rate, combustion chamber temperature, and specific fuel consumption for the two fuels tested and under the two ambient temperature conditions, both during idle and at higher engine regimes. In the idle regime at 0 °C, the kerosene flow is about 0.78% higher than diesel, with the kerosene thrust approximately 1.92% greater. At 20 °C, the kerosene consumption rises by roughly 5.56% compared to diesel, while the thrust increases by about 1.38%. It was observed that at the maximum operating regime, at 0 °C, the kerosene flow exceeds diesel by around 6%, with the kerosene thrust slightly higher, by about 0.63%. At 20 °C, the kerosene consumption rises by roughly 13.19% compared to diesel, while the thrust increases by about 5.91%. In higher regimes, the kerosene consumption surpasses diesel, but the thrust increase is not significant. Thus, diesel’s use as a fuel for the microturbo engine is justified due to its lower consumption at both 0 °C and 20 °C.

Influence of swirl intensity on combustion dynamics and emissions in an ammonia-enriched methane/air combustor

Ammonia (NH3) has been widely considered as a promising carbon-free energy and hydrogen carrier for various applications. The large-scale direct utilization of NH3 as fuel in gas turbine engines is currently attracting significant interest, with strong focuses on improving the efficiency and stability of the system and reducing the emissions of pollutants. The present study experimentally examined the impacts of swirl intensity on combustion stability and emissions in an NH3-enriched premixed swirl-stabilized CH4/air combustor under a wide range of equivalence ratios. Simultaneous high-speed OH* chemiluminescence and particle image velocimetry measurements suggested that increasing swirl intensity resulted in more compact flame shapes and expanded the recirculation zone, which promoted flame stability at higher NH3 ratios. However, under specified conditions, enhancing swirl intensity could increase the instability frequency and amplitude of pressure oscillations. The flame dynamics exhibited different behaviors depending on the swirl intensity. At high swirl intensity, the flames underwent high-frequency, small-amplitude periodic motion. At low swirl intensity, the flames oscillated axially with large amplitude and low frequency. For flow dynamics, the stability of the vortex at high swirl intensity contrasted with the periodic vortex shedding at low swirl intensity. Furthermore, the two-dimensional Rayleigh index indicated that the dominant positive thermoacoustic coupling regions were located near the flame shear layers and flame tail at low and high swirl intensities, respectively. Finally, the experimental results showed that swirl intensity affected pollutant emissions by influencing the temperature of combustion chamber and gas mixing efficiency. The pathway of fuel-type NOx was found to be dominant in the NOx emission of the NH3/CH4/air flames.

Design of A Portable Solid-Fuel Rocket Stove

The depletion of fossil fuels is a hot topic of discussion these days. This is due to the increasing use of fossil fuels in human life. In terms of the increase in fuel and gas prices, we realise that the energy consumption that is increasing from year to year is not balanced with the availability of energy sources, which affects households that use fuel in the cooking process. So a design was carried out to make an ergonomic solid fuel stove with the aim of not using fuel anymore in the cooking process, in this design, the stove is designed to be more flexible and get a portable biomass rocket stove design by considering social aspects, performance, local resources, economy, environmentally friendly. Biomass fuels are solids, liquids or gases produced from organic matter.. Biomass fuels used in solid fuel stoves such as firewood, charcoal, briquettes and pellets. Each biomass fuel has different properties and characteristics. The designed portable rocket stove consists of several main parts namely combustion chamber, chimney, air duct, pan spot and cassing, using stainless steel material. The test results include combustion chamber and water temperature during the process, thermal efficiency, combustion rate and specific fuel consumption under cold start and hot start conditions. After hot start, it is found that the use of a chimney on a portable stove designed using coconut shell fuel is more effective than without a chimney. Shorter boiling time of 1 minute, greater combustion rate of 0.13 grams/minute, higher thermal efficiency of 2% and lower specific fuel consumption of 9.11 grams/litre of water when the stove uses a chimney.

Exergetic analyses of air-fuel preheated cogeneration plants in food production

Lower emissions and better performances in food production also affect the cost, the environmental effects, and the quality of the products of the agriculture and food industry. The aim of this study is to investigate and to analyze the exergetic performance of the production of heat exergy and power, to reuse waste heat and to give optimum reaction and to adapt to changing demands of the food production process and agriculture. Because of those reasons, an air fuel preheated (recuperative) cogeneration plant is taken to analyze the exergetic performance and working conditions by using exergy analysis and 1st and 2nd laws of thermodynamics. Energy and exergy efficiencies, combustion chamber and gas-turbine outlet temperatures, electric-heat exergy rates, specific works, and total electric and heat energies and exergies are calculated by taking various environmental temperatures and various excess air coefficient. Effects of the environmental temperatures and the excess air coefficient on the exergetic performance of the recuperative cogeneration plants were calculated, obtained, and discussed. For the best exergetic performance and working conditions, some recommendations were done for agriculture and for the food production process. In that study, it is found that, the recuperative cogeneration plants can obtain and give the best solutions and can adapt to changing demands of heat and electric rates. Also, it was found that, lower ambient temperatures give better electric efficiency, but lower heat exergy and electric rates. However, higher excess air coefficient increases the performance of the recuperative (air fuel preheated) cogeneration plants.

A numerical study of the effects of jet-aft wall temperatures on the dynamics of jets in hypersonic crossflows

For high-speed vehicles such as scramjets, internal combustion chamber temperatures play an important role in the engine performance, with the influence of the temperature on the fuel injection dynamics being of key interest. In this study, large eddy simulations are employed to investigate a sonic jet in a Mach 5 crossflow with a momentum flux ratio of 5.8 and the parametrization of the temperature of the wall aft of the jet. Both uniform and non-uniform wall temperatures are analyzed, with two jet-to-crossflow temperature ratios of 8.06 and 3.23 investigated. It is found that the wall temperature primarily influences the near wall flow, with a small amount of entrainment into the jet plume via the counter-rotating vortex pair as the low velocity flow is limited by the near-wall shear layer. It is found that the aft-recirculation zone is expanded with the increasing wall temperature, which has the effect of increasing the penetration of the jet plume into the far field. Five recirculation regions are observed ahead of the jet, which are noted to result from the interaction between the crossflow and jet flow for both the adiabatic and temperature-controlled cases, with jet fluid flowing into the forward boundary layer, and thus near-wall mixing is observed. Horseshoe vortex strength is seen to dissipate when passing over the cooled walls, thus reducing the mixing potential near the wall, where the opposite is true for heated walls. Lateral spread of the horseshoe vortices is seen to increase with cooled walls, increasing the near-wall mixing potential.

Experimental Study of Combustion Chamber Performance Utilizing Biochar from Empty Fruit Bunch (EFB) as Fuel with Variation in Excess Air

Palm oil mill waste is abundantly available in Indonesia as biomass. However, the inorganic part of biomass fuels causes problems related to the ash generated, leading to slagging and fouling. The slagging and fouling as deposits form on heat transfer surfaces is one of the main problems associated with biomass combustion. Reducing the deposit formation will improve the boiler’s performance. As low-calorific biomass energy, the empty fruit bunch (EFB) can be converted into high-calorific biomass solid fuel as biochar using pyrolysis. This study investigates the potential of biochar as a solid fuel that can be used as a mixed fuel with coal (cofiring) in boilers in power plants. Biochar, produced from the pyrolysis of EFB at a temperature of 500 °C, is used as fuel in the combustion chamber of a laboratory-scale boiler. The variations in excess combustion air from 20% to 40% were implemented to analyze the slagging and fouling index as well as the efficiency of the combustion chamber. From analysis, the highest combustion chamber temperature appears at 30% excess air, and the lowest was at 20%. The biochar with 30% excess air combustion has a lower potential for slagging and fouling formation. Moreover, the highest combustion chamber efficiency is around 88.06%.

Theoretical study on the inherent relationship between laminar burning velocity, ignition delay time, and NO emission of ammonia-syngas-air mixtures under gas turbine conditions

This study utilizes numerical methods with Chemkin 19.2 and Matlab R2020a to investigate the relationship between laminar burning velocity and free radical concentration, the relationship between laminar burning velocity and ignition delay time, and the relationship between NO emissions and free radical concentration for ammonia-syngas-air combustion. Additionally, it explores the mechanisms by which these three relationships change with variations in the initiate temperature and chamber pressure of the combustion chamber. Furthermore, to understand the theoretical foundation of these relationships, the study examines four global flame parameters: adiabatic flame temperature (Tad), activation energy (Ea), Zeldovich number (Ze), and Lewis number (Le). The results indicate that changes in initial temperature and pressure influence the laminar burning velocity by modifying the concentration of H + NH2 radicals. Simultaneously, alterations in initial temperature and pressure also adjust the quantitative relationship between laminar burning velocity and the concentration of H + NH2 radicals. Additionally, the results reveal that variations in initial temperature and pressure impact NO emissions by altering the concentration of H + NH2 radicals. Following a comprehensive examination of both the theoretical relationship between laminar burning velocity and ignition delay time and the empirical relationship between laminar burning velocity and ignition delay time, a relationship between the density-weighted collision rate BC in the laminar burning velocity expression and the pre-exponential factor A in the theoretical expression for ignition delay time was observed, where BC2A = C0∙Tuδ∙Pε (where C0, δ and ε are constants). This offers a potential methodology for investigating thermal effects, chemical effects, and transport effects in complex mixed fuel combustion processes. Further investigation demonstrates that an increase in the initial temperature within a gas turbine combustion chamber will, by promoting thermal effects, inhibiting transport effects, and altering chemical effects, affect the quantitative relationship between laminar burning velocity and ignition delay time. Further research reveals that an increase in the initiate temperature of the gas turbine combustion chamber affects the quantitative relationships between laminar burning velocity and ignition delay time by promoting thermal effects, suppressing transport effects, and chemical effects. An increase in chamber pressure influences these relationships by enhancing chemical and transport effects while inhibiting thermal effects. Moreover, the functions characterizing chemical effects, transport effects, and thermal effects can be reasonably approximated in this study as functions of initial temperature and pressure, especially under the specific F-class gas turbine conditions presented herein. This finding holds significance for the design of combustion chambers under actual gas turbine operating conditions.

The effect of the ceramic foam cell structure on the combustion performance of porous media burner: experimental study

To investigate the effect of the ceramic foam cell structure on the combustion characteristics, a porous media burner(PMB) composed of foamed ceramic plates with Kelvin and WP cell models as structural features was designed and developed. The combustion chamber temperature, lean combustion limit, radiation efficiency and flue gas emission characteristics of the burner were analysed in the combustion of methane. The results show that with the same pore density, skeleton diameter and operating parameters, the combustion chamber temperature and radiation efficiency of the WP model are higher than those of the Kelvin model, while the CO and NOx emissions of WP model have an opposite tendency. When the ceramic foams are composed by WP cell model, under the same pore density and operating parameters, the burner has better combustion performance when the skeleton is thin. The combustion chamber temperature and radiation efficiency are higher, CO and NOx emissions are lower, and the lean combustion limit equivalent ratio is lower.

Identify The Cause and Effect of Detonation In The Main Engine

In the process of shipping, the main engine must always be maintained in prime condition to support the smooth sailing of a ship. In the main engine, there are often oddities or things that are not common in the main engine, one of which is knocking. The purpose of this study is to identify detonation that occurs in the main engine, analyze the causes and consequences of detonation. The research method used in this research is qualitative. Sources of research data obtained from data collection techniques through observation, interviews, documentation, and data validity techniques using internal validity. The place and time of the research were conducted at MV. Tanto Hemat for one year. SWOT method to analyze various factors that can be used to optimize blasting systematically against strengths, weaknesses, opportunities, and threats. The study results identify detonation in the main engine, namely ignition delay and pre-ignition in the main engine. Factors that cause detonation in the main engine are poor fuel quality, high pressure and temperature in the engine combustion chamber, and improper combustion timing. The impact caused by detonation on the main engine is detonation will cause an increase in fuel consumption, damage to engine spare parts, and carbon buildup in the combustion chamber.

Characteristics of Olive Oil Droplet Combustion with Various Temperatures and Directions of Magnetic Fields in the Combustion Chamber

This study examines the effects of temperatures and directions of the magnetic fields in the combustion chambers on flame characteristics for boiler combustion in power generation systems by burning olive oil droplets. The variations in the temperature of the combustion chamber are 40°C, 50°C, and 60°C. Meanwhile, the directions of the magnetic fields are the repulsive magnetic field (north-north) and the attractive magnetic field (north-south). In the experiment, a droplet of olive oil was placed at a type K thermocouple junction between the two bar magnets. A 250 fps high-speed camera recorded the flame from its ignition to its extinction. The results of this study found that temperature and direction of the magnetic fields in the combustion chamber have an effect on the characteristics of the flame, where the attractive magnetic field (north-south) resulted in increased burning of droplets, round flame, low altitude, increased temperature, and shorter ignition delay time, compared to the repulsive magnetic field (north-north) and without a magnetic field. Furthermore, the combustion chamber temperatures of 40°C, 50°C, and 60°C produced flame temperatures of 799.94°C, 829.25°C, and 879.50°C, and flame heights of 5.97 mm, 5.35 mm, and 4.23 mm, respectively. The strong magnetic fields increased the concentration of oxygen and fuel molecules around the combustion reaction zone, causing shorter droplet combustion and releasing a large amount of energy. These findings are beneficial for designing efficient industrial heat generators with a magnetic field. The results of this study are therefore crucial as a basis for considering the substitution of fossil fuels with environmentally friendly vegetable oils.