Temperature In Combustion Chamber Research Articles

Temperature measurement method of high temperature and high pressure flow field based on wavelength modulation spectroscopy technology

温度是衡量燃烧效率的重要参数之一, 温度的测量对工业燃烧过程的节能减排控制和发动机状态诊断等都具有重要意义. 可调谐半导体吸收光谱技术是一种非侵入式测量技术, 具有较强的环境适应性, 可实现快速、原位检测. 本文基于H₂O在7185.6, 6807.8以及7444.35/37 cm^–1三条吸收线集成测量系统, 三只激光器为时分复用方式, 选择波长调制技术, 利用扣除背景的1<i>f</i>归一化2<i>f</i>信号反演燃烧流场温度, 通过直接比较实际测量的谐波信号与建立的吸收模型获得的谐波信号, 实现了某型号发动机模型喷口温度的准确测量, 测量系统时间分辨小于1 ms, 最高测量温度和最大压强可到1512 K和10.58 atm (1 atm = 1.013 × 10⁵ Pa), 测量误差小于5.68%, 验证了该测量方法的实用性和系统的稳定性.

Endoscopic visualization of engine combustion chamber using diesoline, diesosene and mineral diesel for comparative spatial soot and temperature distributions

Diesel engines are the prime workhorses of global transport and agriculture sectors. However, they emit significantly higher quantities of oxides of nitrogen (NOx) and particulate matter (PM). This unique study involves evaluation of in-situ spatial distribution of temperature and soot in the engine combustion chamber using high-temperature endoscopy, while the engine was being fuelled with emerging fuels so that suitable strategies for effective control of emissions could be devised. Two new test fuels namely diesosene (K20) (20% kerosene (v/v) blended with mineral diesel) and diesoline (G20) (20% gasoline (v/v) blended with mineral diesel) were compared with the baseline mineral diesel in a conventional direct injection compression ignition (DICI) engine. These two fuels represent relatively inferior quality diesel, which is increasingly available in global markets due to gradually exhausting petroleum resources and is produced from heavier/residual crude left in the oil wells. Diesoline showed superior combustion characteristics compared to diesel and diesosene. Endoscopic visualization technique emerged to be an effective tool, wherein real-time combustion characteristics of various test fuels could be successfully evaluated in a time efficient and cost-effective manner. This research article shows the experimental implementation of an emerging optical technique, which might be potentially useful in designing more efficient engines in quicker turn-around time for research and development.

A model-based and experimental approach for the determination of suitable variable valve timings for cold start in partial load operation of a passenger car single-cylinder diesel engine

A manipulation of the charge exchange allows controlling the amount of residual gas during engine warm-up. The residual gas during the warm-up phase leads to an increase of the exhaust gas temperature and supports to reach the exhaust after-treatment system operating temperature faster. In addition, the warm residual gas increases the combustion chamber temperature, which reduces the HC and CO emissions. However, fuel consumption increases. For that reason, such heating measures should be the best compromise of both, exhaust gas temperature increase and engine efficiency, in order to provide efficient heating strategies for passenger car diesel engines. Therefore, simulative and experimental investigations are carried out at the Institute of Internal Combustion Engines of the Karlsruhe Institute of Technology to establish a reliable cam design methodology. For the experimental investigations, a modern research single-cylinder diesel engine was set up on a test bench. In addition, a one-dimensional simulation model of the experimental setup was created in order to simulate characteristics of valve lift curves and to investigate their effects on the exhaust gas temperature and the exhaust gas enthalpy flow. These simulations were based on design of experiments (DoE), so that all characteristics can be used sustainably for modeling and explaining their influences on the engine operation. This methodology allows numerically investigating promising configurations and deriving cam contours which are manufactured for testing. To assess the potential of these individual configurations, the results obtained were compared with each other as well as with the series configuration. Results show that the combination of DoE and one-dimensional simulation for the design of camshaft contours is well suited which was also validated with experimental results. Furthermore, the potential of residual gas retention by favorable configurations with a second event already revealed in various publications could be confirmed with respect to exhaust gas temperature increase and engine efficiency.

Palm oil kernel shell as solid fuel for the commercial and industrial sector in Ecuador: tax incentive impact and performance of a prototype burner

The Ecuadorian industrial and commercial sectors are in general supported in the use of diesel for energy purposes. An alternative to replace diesel could be the use of palm oil residual biomass as solid fuel. It is estimated that 57.7% of the capital costs required to implement a biomass boiler that use untreated palm oil kernel shell (KS) as fuel in replacement of a diesel boiler would be covered by in force tax incentives. Nonetheless, untaxed and subsidized diesel utilization coupled to the important capital and operating costs associated to the biomass boiler results in relatively high payback periods, within the range of 6 to 7.9 years. Analyzing a base case, it is observed that replacement of diesel by KS results in a reduction of 8 times the fuel costs. Implementation of pre-treatment processes (e.g. pelletizing) could increase the KS price, affecting the potential to lower the costs of thermal energy production. Accordingly, utilization of raw KS for thermal energy production was demonstrated using a horizontal burner prototype. The experimental analysis of the KS combustion process shows that combustion efficiency (99.8%) is as high as that observed in other type of biomass burners. During the steady state operation periods, CO concentration in the flue gases (260.1 mg/Nm3) was below the limit established by the European standards for solid fuel boilers (500 mg/Nm3). Ash sintering was observed in the grate during the combustion experiments. The ash discharge process induced periodic fluctuations in the combustion chamber temperature profile as well as fluctuations in the flue gas composition. Despite these localized and periodic temperature and gas composition fluctuations, in the whole, and considering longer periods of operation, the combustion system was under steady state conditions and showed to be suitable for energetic valorization of untreated KS.

Optimization of a triple cycle based on a solid oxide fuel cell and gas and steam cycles with a multiobjective genetic algorithm and energy, exergy and economic analyses

The current study is directed at the optimization and energy, exergy, and economic analyse of a solid oxide fuel cell, integrated with gas and steam trigeneration systems. The variables considered are the fuel cell’s temperature and pressure, air-to-fuel molar ratio, the compressor and gas turbine pressure ratio, combustion chamber temperature, steam cycle pinch point. The objective functions are the exergy efficiency and the electricity cost. The results show that by selection of the optimal values of the fuel cell’s temperature and pressure, air-to-fuel molar ratio, compressor and gas turbine pressure ratio, and the cycle pinch point as 809.8 K, 360 kPa, 2, 2.05, 11.6, and 34.9, the exergy efficiency is increased by 8%, and the produced electricity cost is reduced by 9.7%. The sensitivity analysis shows that an increase in compressor pressure ratio leads to a decrease in the energy and exergy efficiencies and entropy production rates. A change in air-to-fuel molar ratio from 2 to 3 causes the triple cycle electricity cost first to increase and then to decrease.

Experimental analysis of NOx reduction through water addition and comparison with exhaust gas recycling

The diesel engine requirements regarding the reduction of exhaust emissions, especially nitrogen oxide (NOx) and particulate matter (PM) are becoming more stringent year by year. A current method used for NOx control is exhaust gas recirculation (EGR). However, this approach significantly increases the production of soot for medium and high rates. Water addition can also be used for NOx control, achieving 50% NOx reduction rates in relation to EGR with a lower production of soot and without additional carbon monoxide (CO) and hydrocarbons (HC) substantially. This paper analyses the weaknesses and the strengths of adding water into the intake manifold with a flow-blurring injector for NOx reduction on a current technology diesel engine with multiple injection thorough a proprietary tool for heat release rate that considered real gas properties. A reduction of NOx emissions around 60–70% was achieved with water injection at different loads and speeds. Besides, a clear relationship was established between the minimum attainable NOx emission and the thermal capacity of the load (air plus water), this result stablish the hard relationship between NOx formation and combustion chamber temperature and therefore shows the strong dependence of the Zeldovich mechanism.

Effect of biodiesel fuel from soybean oil on exhaust gas and combustion chamber temperature of diesel engine

Several researchers have researched combustion engines, especially those that use biodiesel fuel. However, most of the biodiesel raw materials used are derived from crude palm oil, castor seeds, used cooking oil, and palm oil mill effluent. This research uses biodiesel fuel with raw material from soybean oil and still very rarely done. Experimental results show that specific fuel consumption increases along with the increase in the biodiesel composition of soybean oil in the fuel mixture. The amount of CO and HC exhaust emissions decreased when using fuel B10, B20 and B30. Experimental data show that maximum power is 1.26 kW, specific fuel consumption is 373.15 g/kWh and maximum thermal efficiency is 23.04% when using diesel fuel. The maximum temperature of the diesel engine combustion chamber is obtained at 507.86°C when using diesel fuel. Minimum combustion temperature is obtained when the diesel engine uses B30 of 388.49°C, and this condition is strongly influenced by calorific value of the fuel.

Analysis of the fuel spray diversity in the opposed-piston engine

Experimental analysis of combustion in CI engines is difficult due to the very short duration of this process and the unfavourable thermodynamic conditions prevailing in the combustion chamber (high pressure and temperature). An alternative is to perform numerical calculations using the CFD method based on a defined combustion model. Such an approach was used in this paper to investigate the influence of different fuel injection configurations and different swirl ratio on selected parameters of the combustion process in the designed two -stroke opposed piston engine. The combustion chamber of the tested engine was formed of two movable surfaces of pistons. The AVL Fire software was used to perform the simulation. As a result of the calculations, the dependence of rate of heat release, burnt mass fraction, mean pressure in cylinder and heat transfer coefficient on defined calculation cases was obtained. In addition, a spatial distribution of the combustion stream of injected fuel was obtained. On the basis of the results obtained, conclusions regarding the impact of the fuel injection configuration and the swirl ratio on the obtained engine performance were presented.

Particulate Bound Trace Metals and Soot Morphology of Gasohol Fueled Gasoline Direct Injection Engine

Direct injection spark ignition or gasoline direct injection (GDI) engines are superior in terms of relatively higher thermal efficiency and power output compared to multipoint port fuel injection engines and direct injection diesel engines. In this study, a 500 cc single cylinder GDI engine was used for experiments. Three gasohol blends (15% (v/v) ethanol/methanol/butanol with 85% (v/v) gasoline) were chosen for this experimental study and were characterized to determine their important fuel properties. For particulate investigations, exhaust particles were collected on a quartz filter paper using a partial flow dilution tunnel. Comparative investigations for particulate mass emissions, trace metal concentrations, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) analyses, and high-resolution transmission electron microscopy (HR-TEM) imaging of the particulate samples collected from different test fuels at different engine loads were performed. For majority of the experimental conditions, gasohols showed relatively lower trace metal concentration in particulates compared to gasoline. HR-TEM images showed that higher engine loads and presence of oxygen in the test fuels increased the soot reactivity. Multicore shells like structures were visible in the HR-TEM images due to growth of nuclei, and rapid soot formation due to relatively higher temperature and pressure environment of the engine combustion chamber. Researches world-over are trying to reduce particulate emissions from GDI engines; however there is a vast research gap for such investigations related to gasohol fueled GDI engines. This paper critically assesses and highlights comparative morphological characteristics of gasohol fueled GDI engine.

Differences in ignition and combustion characteristics of waste-derived oil-water emulsions and coal-water slurries containing petrochemicals

The creation of general-purpose combustion chambers and drafting of regulations (unified technologies) which would secure efficient combustion of complex fuel compositions necessitates reliable experimental data concerning the main ignition and combustion characteristics of high-potential oil-water emulsions, coal-water slurries and coal-water slurries containing petrochemicals. In the conducted experiments, we varied the main factors of heating, ignition and combustion processes: properties and concentrations of solid and liquid fuels, the temperature in the model combustion chamber, and initial sizes of fuel droplets. It was established that ignition delay times of oil-water emulsions and coal-water slurries containing petrochemicals based on typical industrial waste can differ 3–4 times. The combustion heat of typical waste industrial oil (collected from power plants after use) makes up 50–90% of the total combustion heat of oil-water emulsions and coal-water slurries containing petrochemicals. The main anthropogenic emission concentrations (sulfur and nitrogen oxides) are 5–6 times higher from burning oil-water emulsions than from burning coal-water slurries containing petrochemicals. We have defined thermal conditions providing close values of the main combustion parameters for oil-water emulsions and fuel slurries. Using two approaches, we have calculated relative efficiency indicators (criteria) of burning high-potential oil-water emulsions, coal-water slurries, and coal-water slurries containing petrochemicals versus coal. These criteria take into account environmental, economic and energy performance. Environmental and energy performance indicators of coal-water slurries containing petrochemicals are 35–90 times higher than those of oil-water emulsions, and 6–16 times higher than those of coal dust fuel.

Thermal analysis of Nano ceramic coated piston used in natural gas engine

Nano ceramic coatings have low thermal conductivity which can provide good heat insulation properties, and therefore they have been widely used in industrial design as thermal barrier coatings (TBCs). In the design of internal combustion engines, TBCs have been used on combustion chamber components to improve engine performance. In this paper, improvement in the working performance of natural gas engines is demonstrated when an aluminum alloy piston is sprayed with a Y2O3 partially stabilized zirconia (PYSZ) ceramic coating. Steady-state thermal analyses were used to determine the effects of the ceramic coating on temperature distributions. Output was compared with results from an uncoated conventional piston using the finite element method. Results show that the temperature at the top surface of coated piston is significantly higher (about 44% or 153 °C higher) than that of the uncoated piston. This higher combustion chamber temperature results in better engine thermal efficiency and lower emissions. Simultaneously, the temperature of the coated piston substrate is much lower (about 12% or 43 °C lower) than that of the uncoated piston. The lower metallic substrate temperature provides better thermal fatigue protection for the piston.

Time-resolved chemical composition of small-scale batch combustion emissions from various wood species

Small-scale batch combustion of wood is a major source of fine particles, black carbon emission and polycyclic aromatic hydrocarbons in Finland. The mass and chemical compositions of batch combustion emissions are known to be highly time-dependent. In this study, the gaseous and particulate batch combustion emissions of three European wood species (beech, birch and spruce) were quantified in detail with an extensive set of online analysers, including a soot particle aerosol mass spectrometer (SP-AMS) for real-time detection of particulate chemical composition. Ignition and a new batch addition on top of glowing embers were identified as the primary low temperature events during which both particulate and gaseous organic emissions peaked. The flaming combustion created high temperature conditions and produced increased emissions of refractory black carbon (rBC) and PAHs. The residual char combustion phase was characterized by low particulate mass emission consisting mainly of alkali salts and elevated concentrations of gaseous organic emissions and CO. Overall, hardwood species (beech and birch) had the highest PM1 emissions, and the difference between the lowest average emission (spruce) and the highest (birch) was more than 3-fold. The increasing combustion chamber temperature during sequential combustion of wood batches was found to decrease the carbonaceous fraction of the PM as well as OC/EC ratio, as the result of more efficient secondary combustion.

An Experimental Technology of Drying and Clean Combustion of Biomass Residues

In the present study, the drying and combustion of solid biomass residues are developed. The combustion of the residues inside a boiler and a stove have been done. We used three types of solid biomass residues (i.e., cork, pine pellet and olive pomace). These residues have been dried by using screw dryers. Experimental installation has been used for a series of thermal drying tests of the residues by measuring the temperature inside the dryer and their moisture contents. A laboratory screw dryer was used to dry the olive pomace by using hot gases from a chimney of a biomass stove. Elemental and proximate analyses, as well as the higher heating value (HHV) of the raw materials, have been determined. In the experiments, moisture content variation of the residues and drying temperatures are obtained. These residues are dried several times under the same drying conditions to achieve the final moisture content rate. On the other hand, the temperature of combustion chamber of the boiler has been measured under different conditions. It has been found that by increasing hot gas temperature, the drying rate is increased. Finally, it has been found that the drying of these residues increases their calorific values and reduces the emissions.

Simulation of the combustion process for a CI hydrogen engine in an argon-oxygen atmosphere

Hydrogen combustion in a noble gas atmosphere increases the combustion chamber temperature, and the high specific heat ratio of the gas increases the thermal efficiency. In this study, nitrogen was replaced by argon as the intake air along with pure oxygen to supply the engine. The objectives of this study are to determine the effects of different engine parameters on combustion and to analyse the emissions from hydrogen combustion in an argon-oxygen atmosphere. This research was conducted through simulations using CONVERGE 2.2.0 software, and the YANMAR engine NF19SK model was used to determine the basic parameters. Changing the injector location affects the pressure and temperature in the combustion chamber. With increasing compression ratio, the pressure increases more rapidly than the temperature. However, combustion at high compression ratios decreases the maximum heat release rate and increases the combustion duration. Hydrogen combustion at ambient temperatures below 1200 K follows the Arrhenius equation.

Experimental and numerical study of the characteristics of biomass suspension combustion in a hot-water boiler

Biomass powder fuel is an abundant and widely available biomass resource with potential advantages including simple manufacturing process, low energy consumption during processing, high bulk density, convenient storage and transport and high combustion efficiency over other forms of biomass fuels such as bulk, compact block and grain fuels. However, the nature of biomass powder produces a series of issues during combustion including inferior combustion stability, which demands a deep investigation to enhance the energy production and utilization from powder biomass. In this paper, a combined experimental and theoretical study on combustion characteristics is carried out based on a recently developed biomass suspension hot-water boiler with a new design. When the fuel powder concentration is 450 g/m3 and the primary/secondary air ratio is 0.8, the biomass suspension combustion hot-water boiler reaches its optimal condition and the combustion chamber temperature and the thermal efficiency are at their highest levels. The thermal performance of the designed biomass suspension hot-water boiler is tested for the rated condition. Data show that the combustion efficiency and the thermal efficiency reach 97% and 83%, respectively, whereas the harmful gas (CO, SO2, NOx) content in the fumes meet the requirements of the national industrial boiler atmospheric pollutant emission standard in China. The computational fluid dynamics simulation of the temperature field in the furnace shows that combustion of a biomass powder fuel in a pre-combustion chamber and a furnace is not only closely related to the oxygen supply but also related to the airflow ratio and the furnace temperature. The simulated results show that the furnace temperature field, the primary and secondary airflow streamlines, the biomass powder grain movement trajectory and the component field distribution are in agreement with the experimental results. Our findings may help to design an efficient biomass suspension hot-water boiler.

External Ballistics Simplified Model of the “RT – 400” Rocket Aerial Target

“RT-400” rocket aerial target system is described in the paper; research method of its simplified external ballistics characteristics is presented and the obtained results are discussed. This system was designed, tested, and produced by a research team of the Institute of Defence Technologies at Kaunas University of Technology and successfully implemented in practice. One of main aims of this paper was to develop external ballistics’ model of a rocket propelled aerial target which would enable obtaining various ballistic parameters of the investigated vehicle such as its acceleration, velocity, flight angle, flight range and trajectory using as input the internal ballistics data obtained at earlier experimental research of the “RV-12K” rocket motor in a static horizontal test stand for thrust measurements and determination of other internal ballistics’ characteristics such as combustion chamber temperature and pressure. During the experimental research process of the vehicle, under test site conditions, the main aim was to compare accuracy of the obtained external ballistics simulation data with the data obtained during experimental approaches using additional measurement techniques such as radar tracking and crash site and launch site GPS coordinates marking.

An experimental study of emission characteristics from cylindrical furnace: Effects of using diesel-ethanol-biodiesel blends and air swirl

In this research, experimental investigation was undertaken to find the effects of air swirling on pollutant emissions in a cylindrical combustion chamber fuelled with diesel-biodiesel-ethanol blends. At the first, a burner system with various radial air swirl generator (the vane angles were 15°, 25°, 35°, 45°, 60° and 90°) attached to the combustion chamber of 400 mm inside diameter and 2000 mm length. Fuel blends were D100, D85B10E5 (85% diesel, 10% biodiesel and 5% Ethanol on a volume basis), D80B10E10, D75B20E5, and D70B25E5. CO, HC, CO2 and NOx as the emission characteristics were determined in this research. Moreover gas temperature in a cylindrical combustion chamber was reported. According to the results, the minimum CO and HC emissions belong to fuel blend D70B25E5 and air swirl generator with the vane angles of 15° and the maximum CO and HC emission occurs for net diesel (D100) and swirl air vane angle of 90°. Moreover, D80B10E10 has the maximum CO2 emission. It shows that ethanol can more effective to increase in CO2 values than that of biodiesel. Besides, the minimum CO2 emission obtained for fuel blend D100. The minimum value of NOx emission occurs for D100 and swirl air vane angle of 45°. In addition, air swirling condition with higher vane angles of 45° leads to higher premixed combustion and temperature and causes an increase in NOx emission. Moreover, the maximum value of NOx emission will be for D70B25E5 because of higher biodiesel content as an oxygenated fuel. The results indicated that the mean temperature of combustion gas increases when biodiesel content of fuel mixture increases. On the other hand, the mean temperature of combustion gas decreases by the addition of ethanol in fuel mixture.

Analysis of temperature field of grain and drying medium for grain drying integrated mechanical device.

In order to improve the working efficiency of the drying tower and the hot blast stove in the process of grain drying, this paper proposes a method to solve the problems of air pollution and energy waste caused by excessive combustion or insufficient combustion of the hot blast stove. Based on finite element analysis, this paper uses ANSYS software to simulate the drying process of grain. This paper briefly introduces the grain drying device model and working mechanism, analyzes the temperature field of the drying device, and studies the influence on the drying effect of the working parameters (hot water, hot air, hot air hot blast stove combustion temperature) during the grain drying process. The results show that the hot air temperature is 85°C, the hot water temperature is 90°C, the combustion chamber temperature is 480°C, the grain drying effect is good, the combustion efficiency of the combustion furnace is the best, and the energy utilization rate is the highest.

Relation between flame chemiionization and variable-volume combustion chamber temperature and pressure

The article presents the results of investigating the relation between flame chemiionization and the flame temperature and pressure in a variable- volume combustion chamber. Functional dependences of flame temperature and maximum pressure on the electron current caused by flame chemiionization, fundamental characteristics of flame propagation and combustion efficiency are presented. Comparison of the temperature calculated by the proposed method with experimental data shows that with the excess air factor of 0.8 to 1.15, the precision is more than 85%. Comparison of the maximum pressure obtained experimentally and calculated by the refined Vibe model, using the proposed formulas, showed good agreement. The results of the work can be used to predict and monitor maximum flame temperature and pressure in the combustion chamber of an internal combustion engine and other power plants using an ionization probe.

Analysis and experimental investigation of ceramic powder coating on aluminium piston

Energy conservation and efficiency have always been the quest of engineers concerned with internal combustion engines. The diesel engine generally offers better fuel economy than its counterpart petrol engine. Even the diesel engine rejects about two thirds of the heat energy of the fuel, one-third to the coolant, and one third to the exhaust, leaving only about one-third as useful power output. Theoretically if the heat rejected could be reduced, then the thermal efficiency would be improved, at least up to the limit set by the second law of thermodynamics. Low Heat Rejection engines aim to do this by reducing the heat lost to the coolant. Thermal Barrier Coatings (TBCs) in diesel engines lead to advantages including higher power density, fuel efficiency, and multifuel capacity due to higher combustion chamber temperature. Using TBC can increase engine power by 8%, decrease the specific fuel consumption by 15-20% and increase the exhaust gas temperature by 200K. Although several systems have been used as TBC for different purposes, yttria stabilized zirconia with 7-8 wt.% yttria has received the most attention. Several factors playing important role in TBC life include thermal conductivity, thermo chemical stability at the service temperature, high thermo mechanical stability to the maximum service temperature and thermal expansion coefficient (TEC). This work mainly concentrates on the behaviour of three TBC powders under the same diesel engine conditions. This work finds out the best powder among yttria, alumina and zirconia to be used as a piston coating material i.e., the one resulting in lowest heat flux and low side skirt and bottom temperature has been chosen for the coating purpose. This work then analyses the coated sample for its surface properties such as hardness, roughness, corrosion resistance and microstructural study. This work aims at making it easier for the manufacturers choose the coating material for engine coating purposes and surface properties for operating them in their service period.