Maximum Rate Of Pressure Rise Research Articles

Experimental study on aerosol explosion characteristics and flame propagation behavior of aluminum/ethanol nanofluid fuel

Aluminum/ethanol nanofluid fuel, which exhibits superior emission and combustion properties as well as broad application prospects, is a novel clean fuel produced by dispersing aluminum nanoparticles into liquid ethanol. However, the aerosol explosion characteristics of the fuel are not clear at present. In this study, a visible closed aerosol explosion device was set up to perform the explosion experiment, aiming to investigate the explosion characteristics and flame propagation behavior of the fuel under different blending ratios (0 wt%-10 wt%) and aerosol concentrations (97.53 g/m3-214.81 g/m3). The results showed that, as the blending ratio increased, the maximum explosion pressure Pex, the maximum rate of pressure rise (dP/dt)ex, the explosion index Ka, the maximum flame propagation velocity Vmax, and the average flame propagation velocity V¯ all increased first, reaching their peak values at the critical blending ratio (4 wt%), and subsequently decreased. Similarly, for nanofluid fuel of different blending ratios, the explosion time te was first shortened and then extended, with the minimum value also occurring at 4 wt%. Moreover, an analysis of fuels’ evaporation properties was performed using TGA analysis. The morphologies and compositions of the explosion products were analyzed by SEM, EDS, and FTIR analysis. Based on the above analyses, a reaction mechanism model for the nanofluid fuel was established. This model reveals the influence mechanism of the blending ratio on aerosol explosions, explains the corresponding explosion behavior, and provides a reference for the research and development of nanofluid fuel.

Experimental investigation on weak shock wave mitigation characteristics of flexible polyurethane foam and polyurea

In recent years, explosion shock wave has been considered as a signature injury of the current military conflicts. Although strong shock wave is lethal to the human body, weak shock wave can cause many more lasting consequences. To investigate the protection ability and characteristics of flexible materials and structures under weak shock wave loading, the blast wave produced by TNT explosive is loaded on the polyurethane foam with the density of 200.0 kg/m3 (F-200) and 400.0 kg/m3 (F-400), polyurea with the density of 1100.0 kg/m3 (P-1100) and structures composed of the two materials, which are intended for individual protection. Experimental results indicate that the shock wave is attenuated to weak pressure disturbance after interacting with the flexible materials which are not damaged. The shock wave protective capability of single-layer materials is dependent on their thickness, density and microscopic characteristics. The overpressure, maximum pressure rise rate and impulse of transmitted wave decrease exponentially with increase in sample thickness. For the same thickness, F-400 provides better protective capability than F-200 while P-1100 shows the best protective capability among the three materials. In this study, as the materials are not destroyed, F-200 with a thickness more than 10.0 mm, F-400 with a thickness more than 4.0 mm, and P-1100 with a thickness more than 1.0 mm can attenuate the overpressure amplitude more than 90.0%. Further, multi-layer flexible composites are designed. Different layer layouts of designed structures and layer thickness of the single-layer materials can affect the protective performance. Within the research range, the structure in which polyurea is placed on the impact side shows the optimal shock wave protective performance, and the thicknesses of polyurea and polyurethane foam are 1.0 mm and 4.0 mm respectively. The overpressure attenuation rate reached maximum value of 93.3% and impulse attenuation capacity of this structure are better than those of single-layer polyurea and polyurethane foam with higher areal density.

Experimental study on the explosion characteristics of NH3/DME/air mixtures

Co-firing ammonia (NH3) fuel with dimethyl ether (DME) is a promising approach of achieving clean combustion. However, the fundamental explosion characteristics of NH3/DME blends have not been well understood. This paper presents an experimental study of the explosion characteristics of NH3/DME blends using a spherical constant-volume combustion chamber. The effects of equivalence ratio (ϕ = 0.7–1.5), initial pressure (Pu = 0.05–0.5 MPa), and DME fraction (XDME = 0–100%) on the explosions were examined. The results show that peak explosion pressure Pmax, maximum pressure rise rate (dP/dt)max, and deflagration index KG, vary non-monotonically with equivalence ratio, and reach peak values at around ϕ = 1.1–1.2. DME addition has a positive effect on explosion intensity. Both (dP/dt)max and KG show a linear increase trend with increasing DME, while the growth rate of Pmax decreases with DME fraction. The relatively higher increase in Pmax between 0 %DME and 20 %DME is mainly due to greater heat release. Pmax increases with increasing initial pressure, and this is because of the increase in mixture mass promoting the heat release, and the enhanced possibility of effective collision between molecules of gas mixtures. The influence of initial pressure on (dP/dt)max and KG depends on the equivalence ratio. Both (dP/dt)max and KG show a linear increase with increasing initial pressure at ϕ = 1.0 and 1.5, whereas they are insensitive to initial pressure at ϕ = 0.7. This is because the decrease in laminar burning velocity leads to a significant increase in explosion time at ϕ = 0.7 compared to ϕ = 1.0 and 1.5. In addition, the actual explosion pressure is closely associated with non-negligible heat loss during flame propagation, and the heat loss decreases with the addition of DME, but increases with increasing initial pressure.

Effect of compression ratio and Miller cycle on performance of methanol engine under medium and low loads

Considering the excellent anti-knock property of methanol fuel and the fact that passenger car engines typically operate at medium to low loads, this paper increasing the compression ratio and adopting the Miller cycle to improve the engine's efficiency, based on a methanol engine with compression ratio of 9.5:1. Experimental research is conducted to analyze the engine's combustion and emission characteristics under different operating conditions. The research shows that increasing the compression ratio to 12:1 can effectively reduce methanol consumption under medium to low loads, and applying the Miller cycle on the compression ratio of 12:1 can further improve fuel economy at low loads. Increasing the compression ratio raises the engine's cylinder pressure, maximum pressure rise rate, and cycle-to-cycle variation, thereby enhancing the tendency for knocking. However, the Miller cycle can effectively alleviate this situation while reducing engine pumping losses. From the perspective of emissions at medium and low loads, the high compression ratio reduces CO and HC emissions but increases NOx emissions due to high combustion temperature. The Miller cycle's shorter combustion duration and lower combustion temperature result in higher CO and HC emissions compared to an Otto cycle at the same compression ratio, but NOx emissions are improved.

Combustion characteristics of a turbocharged direct-injection hydrogen engine

The direct injection hydrogen internal combustion engines avoid backfires and have a higher power density, especially when coupled with a turbocharger. However, while previous researches have focused on specific aspects of direct injection hydrogen internal combustion engines, their whole combustion characteristics remain largely unclear. Therefore, this study aims to comprehensively investigate the combustion characteristics of turbocharged direct injection hydrogen internal combustion engines across the entire operating map in order to optimize their performance. The combustion characteristics are hypothesized to be significantly influenced by operating parameters, including the equivalence ratio, spark timing, start of injection, and other relevant factors. To achieve this, the experiments were conducted on a 2.0 L turbocharged direct injection hydrogen internal combustion engine, covering a wide range of operating conditions. Specifically, the engine speeds varied from 1000 to 4000 rpm, loads ranged from 3.7 to 10.6 bar, equivalence ratios spanned from 0.33 to 0.71, spark timing was adjusted within a range of 21 degrees of crank angle, and start of injection varied within a range of 80 degrees of crank angle. The experimental results reveal notable findings regarding the turbocharged direct injection hydrogen internal combustion engine. For instance, the maximum pressure rise rate of the turbocharged direct injection hydrogen internal combustion engine (3.85 bar/°CA at 1500 rpm) at various engine speeds at wide open throttle are greater than those of a turbocharged port fuel injection hydrogen internal combustion engine and a gasoline engine. Furthermore, variations in equivalence ratio and spark timing cause significant increases in pressure rise rate by 328.4% and 233.3%, respectively. The peak pressure rise rate characteristics provide valuable insights for optimizing the noise, vibration and harshness of turbocharged direct injection hydrogen internal combustion engines. Additionally, the burning duration demonstrates an initial increase and subsequent decrease with changes in the start of injection, aiding in the determination of the optimal start of injection for achieving high brake thermal efficiency. Overall, this research provides valuable insights into the macroscopic combustion characteristics of a turbocharged direct injection hydrogen internal combustion engine across different operating conditions. These findings not only can be directly applied to hydrogen internal combustion engines of the same displacement and type, but also can be applied to the design and development of hydrogen internal combustion engines with different displacements and types.

Analysis of explosion and laminar combustion characteristics of premixed ammonia-air/oxygen mixtures

Ammonia is suggested to be a potential carbon-free energy source because of its high volumetric energy density and has attracted attention recently. However, systematic investigations into the explosion characteristics and flame instability of ammonia are still lacking, particularly for low-pressure ammonia-oxygen mixture. The use of low-pressure ammonia-oxygen mixtures could not only benefit for increasing engine's efficiency but also enhance its operational safety. In this study, explosion experiments of premixed ammonia-air/oxygen mixtures are carried out in a 20-L spherical chamber. By adjusting the initial pressure (P0) and equivalence ratio (ϕ), the maximum explosion pressure (Pmax) and maximum rate of pressure rise ((dP/dt)max) are measured. The laminar flame characteristics are analysed simultaneously. The results show that for the ammonia-air mixture, Pmax increases as P0 increases and reaches the peak at ϕ = 1.1; the unstretched laminar burning velocity (SL), Markstein length (Lb), and laminar flame thickness (δ) decrease as the initial pressure increases and reach the peak at ϕ = 1.1. For the ammonia-oxygen mixture, the explosion parameters linearly increase as P0 increases, while the maximum values of the parameters are obtained at ϕ = 1.0; the unstretched laminar burning velocity increases first and then gradually decreases as P0 increases; the maximum SL is 1.14 m/s at P0 = 0.1 MPa and ϕ = 1.0, which is 18 times that of the premixed ammonia-air mixture under the same condition. The schlieren images demonstrate that the buoyancy instability has significant impacts on the premixed ammonia-air flame propagation, while it has negligible impacts on the premixed ammonia-oxygen flame propagation. The effect of hydrodynamic instability on flame propagation could be observed in both the premixed ammonia-air flame at ϕ > 1.0 and the premixed ammonia-oxygen flame at P0 > 0.1 MPa and ϕ < 1.0. In addition, it is proposed that for the premixed ammonia-air flame, the buoyancy instability would remarkably influence the flame propagation when the unstretched laminar burning velocity is < 5 cm/s. The fundamental research on the combustion characteristics of ammonia-air and ammonia-oxygen in this study can provide an experimental reference for the later development of chemical reaction mechanisms, especially for the mechanism suitable for ammonia combustion in oxygen-rich environments. Meanwhile, the combustion characteristics of the ammonia-oxygen mixture at ultra-low pressure also provide a data basis for the possibility of using ammonia fuel as a propellant for hypersonic vehicles in the future.

Effects of Adding Ethanol to Natural Gas-Air Mixture on Combustion and Emissions of Natural Gas-Diesel Dual Fuel Engine Based on GT-Power

ABSTRACT To resolve power reduction and engine knock, we investigate the influence of adding ethanol to the natural gas (NG)-air mixture on the combustion and emissions of NG-diesel dual-fuel (NDDF) engines by numerical analysis. The baseline engine is a 4-cylinder diesel engine. NG and ethanol fuels are injected into the intake port, while diesel fuel is injected directly into the cylinder. The simulation is performed using GT-Power software, and the results are validated using experimental data. The engine speeds are set at 1000, 1800, and 2800 rpm. The engine loads are set at 50% and 75%. The diesel injection ratios are 10% and 20%. The ethanol substitution rate (ESR) varies from 0% to 60% with an interval of 10%. The results indicate that combustion and emissions are improved with the increase in ESR. First, the engine knock is reduced since the maximum pressure rise rate (MPRR) decreases. Second, the power performance and economy performance of the NDDF engine is improved because the indicated thermal efficiency (ITE) and brake mean effective pressure (BMEP) increase. In addition, although the emissions of the NG-ethanol-diesel ternary-fuel engine are higher than that of NDDF engines, some emissions, such as nitrogen oxide (NOx) emissions and carbon monoxide (CO) emissions, are lower than that of pure diesel engines. This suggests that the addition of ethanol can improve the power and economic performance of NDDF engines.

Prediction of Exhaust Gas Temperature of a Diesel Engine Running with Diesel Fuel-biodiesel-1-pentanol Ternary Blends

Diesel engines are utilized in the transportation sector owing to their high efficiency. In recent years, biodiesel and higher alcohols have taken the attention of researchers as promising alternative fuels for diesel engines. In this article, diesel fuel is mixed with corn oil biodiesel at the ratio of 80:20 (v/v). 2%, 5% and 8% of 1-pentanol (v/v) are mixed into the diesel fuel-corn oil biodiesel binary blend for obtaining ternary blends. The impacts of ternary blends on some performance and combustion behaviors of a diesel engine are researched. Power and exponential models to predict exhaust gas temperature linking to maximum pressure rise rate, brake effective power, lower heating value, engine speed, equivalence ratio and latent heat of evaporation are derived through the least square error method. The use of ternary blends results in lower brake effective power (5.4246%-6.0066%), exhaust gas temperature (5.9504%-7.9459%,) and peak cylinder pressure (6.8502%-7.1629%), compared to diesel fuel. The average relative errors are specified as 1.9214% and 2.9749% for the power and exponential models, respectively.

Preparation of modified fly ash-based, core–shell inhibitor and its effect on suppression of Al-Mg alloy dust explosion

Dust explosions caused by energetic metals pose a significant risk to process industries, making it crucial to develop high-performance explosion inhibitors. In this study, the modified power plant solid waste fly ash (FA) was confirmed as a raw material for the preparation of core–shell inhibitors to efficiently suppress dust explosion of Al-Mg alloy. The interfacial compatibility of FA was dramatically improved by using alkali hydrothermal modification and organic modification. It formed a well-coated nano-Mg(OH)2 cladding layer on the surface of modified FA by the heterogeneous nucleation method. In a vertical combustion pipe and a 20 L spherical explosion device, the suppression effect of this novel core–shell inhibitor (FA-2@Mg(OH)2) was investigated. The experimental results showed that the addition of 60 wt% of FA-2@Mg(OH)2 reduced the maximum flame velocity (Vmax), velocity to the top of the pipe (Vtop), and average pulsation degree (Vap) by 87.9 %, 92.5 %, and 87.7 %, respectively, and the peak flame temperature (Tp) declined to 298 °C. The maximum explosion pressure (Pmax) and the maximum explosion pressure rise rate ((dp/dt)max) were reduced by 86.1 % and 92.9 %, respectively. Combining the analysis results of SEM, EDS, XRD, and TG-DSC, the suppression mechanism of FA-2@Mg(OH)2 was explained in depth, mainly from the heat absorption, coating effect, gas dilution, and radical adsorption. This work not only sheds new light on the design of dust explosion suppression functional materials but also broadens the application of industrial solid waste FA.

Knock metrics experimental evaluation for pre-chamber SI engines

The present study analyzes the occurrence of pressure oscillations in engines operating with pre-chambers at stoichiometric conditions, aiming to assess whether the increase in the amplitude of pressure oscillations detected by means of cylinder pressure measurements is related to knock, or it is a result of mass transfer from the pre-chamber to the main chamber. Initially, a literature review of the phenomenon is conducted and several knock indicators are used to evaluate experimental data obtained with a commercial four-cylinder SI engine, equipped with pre-chamber ignition system prototype, at 1500 rpm and 4 bar of IMEP. Among the knock indicators analyzed the excitations of resonance modes, the angle and time-based maximum pressure rise rate, maximum amplitude of pressure oscillations, ringing intensity, and adapted knock index can be cited. Furthermore, a study of the predominant pre-chamber ignition mechanism is carried out, distinguishing torch and jet ignition, which is also correlated with knock occurrence. Therefore, the present study shows the importance of conducting an individual knock analysis for each pre-chamber configuration and presents adequate tools for such a study, in order to guarantee engine integrity while exploring the benefits of the system, without limitations of inappropriate knock thresholds.

Spray and explosion characteristics of methanol and methanol-benzene blends near azeotrope formation: Effects of temperature, concentration, and benzene content

The explosion hazard of flammable liquids leaking to form spray in storage and transportation at ambient temperature has not been systematically investigated. This work presents new results from experimental investigations of the atomization and explosion characteristics of methanol, and methanol-benzene blends forming near the azeotrope under different initial conditions (initial temperature (298.15–318.15 K), methanol concentration (198–514.8 g/m3) and benzene content (41–81%)) in a 20-L spherical vessel. The empirical formulas for Sauter Mean Diameter (SMD) of the droplets and the maximum explosion pressure with respect to the initial temperature and methanol concentration were obtained from the quantitative analysis. Compared to the explosion hazard of pure methanol and methanol-benzene blends spray, the results showed that the maximum rate of pressure rise and maximum explosion temperature of methanol-benzene blends were relatively low. Furthermore, the effect of carbon soot formation on the explosion hazard during explosion development was analyzed.

Study on the active jet spark induced combustion technology for aviation kerosene piston engine

Aviation kerosene is increasingly being used in aviation piston engines because it is safe for use. However, if the traditional compression ignition (CI) mode is adopted for such engines, the high compression ratio will lead to an increase in the weight of moving parts and a decrease in the engine speed, thereby restricting the improvement of the power–weight ratio. If the traditional spark ignition (SI) mode is adopted, a high-performance output cannot be achieved owing to the restriction of knock. To overcome the abovementioned problems and realize kerosene high efficiency and knock free combustion, in this study, we designed a new combustion mode for active-jet spark-induced (AJSI) compound combustion in aviation kerosene piston engines. In order to verify the feasibility of AJSI combustion, a detailed three-dimensional in cylinder combustion simulation model was established, and the combustion process of AJSI combustion was studied. The results showed that the ignition delay period of kerosene could be reduced by 30% in the AJSI combustion mode. Compared to the ordinary SI combustion, the maximum pressure rise rate reduced by 26%, and knock index reduced by 34%. From the research results, AJSI combustion can effectively suppressing knock. In this paper, the combustion mechanism of AJSI combustion is analyzed in detail. The AJSI combustion process in an engine is divided into five stages, and the combustion characteristics are similar to those of SI in the early stage and similar to those of CI in the later stage. The period of similar–SI lasted for a long time, and the temperature and pressure increased gradually, which was mainly used for preparing for the similar–CI. Combustion during the period of similar–CI was intense. Spontaneous combustion of a large amount of premixed fuel occurred during this period, which lasted for a short time, with a rapid release of large amounts of heat. In this process, owing to the rapid combustion, the knock intensity can be decreased.

Effect of combination of explosion venting and chemical barrier on starch explosion suppression in a large scale connected vessels

The explosion of starch poses a potential threat to the process safety of food and energy enterprises in product processing and storage. To control explosion, a 5 m3 columnar tank with a 10 m long connecting pipe at one end and a 700 mm diameter explosion vent at the other end was built as an experimental device. Combined controlled explosion experiments were conducted using a rupture disc with a static activation pressure of 10 kPa and a chemical barrier containing ABC powder with nitrogen as the driving gas to investigate the pressure and flame change characteristics inside the vessel and piping. The experimental results show that the maximum explosion pressure in the connected vessel without explosion venting is 41.21kPa and the maximum pressure rise rate is 5.20 bar/s. Explosion venting reduces the maximum explosion pressure and pressure rise rate in the vessel by 52.31 % and 21.92 %, respectively, and reduces the flame propagation speed in the pipeline, so that the chemical barrier device can effectively isolate the flame when the installation distance is more than 6 m. The N2 and ABC dry powder two-phase explosion suppressant produced an effective inhibition effect through the physical effects of oxygen insulation, heat absorption, and thermal transmission weakening, as well as the chemical effect of eliminating explosive radicals. The explosion venting provides an initial defense by releasing any remaining pressure and heat of the explosion, while the chemical barrier provides a secondary layer of protection by extinguishing the flame and suppressing the explosion in the pipe to prevent further damage. This combination can greatly reduce the risk of equipment damage, injuries, and fatalities caused by explosions in industrial settings.

Inhaled Epoprostenol and Milrinone Effect on Right Ventricular Pressure Waveform Monitoring.

Pulmonary hypertension (PH) and right ventricular (RV) dysfunction are major complications in cardiac surgery. This study aimed to evaluate the change in RV pressure waveform in patients receiving a combination of inhaled epoprostenol and inhaled milrinone (iE&iM) before cardiopulmonary bypass (CPB) and to assess the safety of this approach with a matched case-control group. A prospective single-centre cohort study of adult patients undergoing cardiac surgery administered iE&iM through an ultrasonic mesh nebulizer. RV pressure waveform monitoring was obtained by continuously transducing the RV port of the pulmonary artery (PA) catheter. The final analysis included 26 patients receiving iE&iM. There was a significant drop in mean PA pressure (MPAP) (-4.8 ± 8.7, P= 0.010), systolic PA pressure (SPAP) (-8.2 ± 12.8, P= 0.003), RV end-diastolic pressure (RVEDP) (-2.1 ± 2.8, P < 0.001) and RV diastolic pressure gradient (RVDPG) (-1.7 ± 1.4, P < 0.001) after 17± 9 minutes of iE&iM administration. Patients also had a significant increase in RV outflow tract (RVOT) gradient (3.7 ± 4.7, P < 0.001), RV maximal rate of pressure rise during early systole (dP/dt max) (68.3 ± 144.7, P= 0.024), and left ventricular (LV) dP/dt max (66.4 ± 90.1, P < 0.001). Change in RVOT gradient was only observed in those with a positive pulmonary vasodilator response to treatment. Treatment with iE&iM did not present adverse effects when compared with a matched case-control group. Coadministration of iE&iM in cardiac surgery patients presenting with PH or signs of RV dysfunction is a safe and effective treatment approach in improving RV function. Appearance of a transient increase in RVOT gradient after iE&iM could be useful to predict response to treatment.

Combustion and performance characteristics of a diesel engine fueled with coal-based hybrid fuel at various altitudes

ABSTRACT At high altitude and low pressure, the changes of inlet and exhaust pressure and the combustion environment in the cylinder lead to the deterioration of physicochemical characteristics and combustion in the cylinder of the coal-based mixed fuel. In this research, based on the plateau environment simulation test platform, the combustion characteristics, dynamic performance and fuel economy of the turbocharged diesel engine burned at different simulated altitudes (0 m, 1500 m, 2500 m, 3500 m and 4500 m) were studied. The results revealed that as altitude increased, the coal-based composite fuel caused the diesel engine’s in-cylinder pressure, pressure rise rate, and instantaneous heat release rate to gradually decrease, the flameout period to gradually extend, and the center of gravity of combustion to gradually delay. At low engine speed, the average effective pressure cycle variation rate increased significantly. The coal-based complex fuel diesel engine has increased in-cylinder pressure, torque, and effective thermal efficiency, as well as peak instantaneous heat release rate at high altitude, when compared to diesel combustion. It also causes a reduction in the maximum pressure rise rate, a forward shift in the combustion center of gravity, a reduction in the average effective pressure cycle rate of change, and a shortening of the stall period.

Ammonia-air combustion and explosion characteristics at elevated temperature and elevated pressure

Experimental and numerical study on ammonia-air combustion and explosion characteristics at elevated temperature and pressure was conducted. The results revealed that the ammonia-air flame of different equivalence ratios is quite smooth at elevated temperature and pressure. The laminar burning velocity (LBV) reaches the peak of 0.073 m/s at Ф = 1.1 and increases as increasing initial premix temperature and decreasing initial premix pressure. Maximum explosion overpressure (MEO) and maximum pressure rise rate (MPRR) reach the peak of 0.43 MPa and 0.13 MPa/ms respectively at Ф = 1.1. The theoretical MEO is significantly higher than the experimental results due to heat loss, and the minimum heat loss occurs at Ф = 1.1. MEO, MPRR and heat loss increase with increasing initial premix pressure, and MEO and heat loss decrease with increasing initial premix temperature, while MPRR increases. Okafor mechanism has the best LBV prediction performance among seven mechanisms. And the main elementary reactions affecting LBV are H + O2=O + OH and HNO + HH2+NO.

Effects of ignition location on the characteristics of dust explosion venting at elevated static activation pressure

The effect of ignition location on the pressure characteristics of vented dust explosion was investigated in a 20 L chamber. For internal pressure, the proportion of the venting mixture with different ignition locations coupled with the wall quenching effect dominated the internal pressure curves. Besides, the maximum pressure rise rate was controlled by the residual amount of the fuel and induced turbulence. For external pressure, the ignition location dominated the delay time of the external explosion and the number of pressure peaks. Furthermore, the generation mechanism of pressure peaks was revealed by external pressure curves together with the visualization of the flow field. Eventually, it was found that both the internal and external maximum pressure with central ignition was larger than rear-end ignition and then the front-end. The corresponding dynamic mechanism was theoretically revealed, and a dimensionless prediction model for venting size and maximum external pressure was established.

In-cylinder pressure profiling for CNG/ethanol enriched biodiesel combustion

The current study takes a comparative approach to analyze the In-Cylinder pressure distributions and their effect on the engine combustion stability for a specific diesel engine when fueled with Mahua biodiesel in split injection mode with low reactive CNG/ethanol through port fuel injection. Variations in injection time, main-pilot energy sharing, and reactivity of the fuel mixture are included in this investigation. The engine’s operational and combustion stability during ethanol/CNG enriched Mahua biodiesel operation has been demonstrated by the coefficient of variance of indicated mean effective pressure and maximum rate of pressure rise, respectively. The minimum value of the stability index of maximum pressure rise rate for CNG-biodiesel & ethanol-biodiesel combustion illustrated a 49.23% & 88.07% reduction compared to baseline diesel operation. The minimum value of COVIMEP for the respective fuel strategies registered 83.49% & 40.27% lower measures than the corresponding baseline diesel operation. This inquiry also examines the variance in emission and performance of the test engine with stability indicators. 13.04% & 34.92% higher thermal efficiency have been reported for ethanol-biodiesel operation under the most stable combustion and operating conditions. Significantly lower particulate matter and carbon monoxide footprints have been reported under CNG-biodiesel operation with higher stability conditions.

Cardioprotective Effects of a Selective c-Jun N-terminal Kinase Inhibitor in a Rat Model of Myocardial Infarction.

Activation of c-Jun N-terminal kinases (JNKs) is involved in myocardial injury, left ventricular remodeling (LV), and heart failure (HF) after myocardial infarction (MI). The aim of this research was to evaluate the effects of a selective JNK inhibitor, 11H-indeno [1,2-b]quinoxalin-11-one oxime (IQ-1), on myocardial injury and acute myocardial ischemia/reperfusion (I/R) in adult male Wistar rats. Intraperitoneal administration of IQ-1 (25 mg/kg daily for 5 days) resulted in a significant decrease in myocardial infarct size on day 5 after MI. On day 60 after MI, a significant (2.6-fold) decrease in LV scar size, a 2.2-fold decrease in the size of the LV cavity, a 2.9-fold decrease in the area of mature connective tissue, and a 1.7-fold decrease in connective tissue in the interventricular septum were observed compared with the control group. The improved contractile function of the heart resulted in a significant (33%) increase in stroke size, a 40% increase in cardiac output, a 12% increase in LV systolic pressure, a 28% increase in the LV maximum rate of pressure rise, a 45% increase in the LV maximum rate of pressure drop, a 29% increase in the contractility index, a 14% increase in aortic pressure, a 2.7-fold decrease in LV end-diastolic pressure, and a 4.2-fold decrease in LV minimum pressure. We conclude that IQ-1 has cardioprotective activity and reduces the severity of HF after MI.

Simulation of combustion process in diesel/butanol dual fuel engine

ABSTRACT To investigate the feasibility of diesel engines with high butanol substitution rate (BSR), the performance and emissions of diesel–butanol dual fuel engines are studied numerically. It i based on a four-cylinder diesel engine, which is modified into a diesel–butanol dual fuel engine with port-injected butanol fuel and direct-injected diesel fuel. The simulation is performed using GT-Power software, and simulation results are validated with the experimental data. The engine speeds are set at 1600, 2300, and 3600 rpm, respectively. The engine load is set at 25%, 50%, and 75% engine load, respectively. The BSR varies from 0% to 80% with an interval of 10%. The results show that, with the increase of BSR, the peak cylinder pressure (PCP), and the maximum pressure rise rate (MPRR) decrease, while the brake mean effective pressure (BMEP) and the indicated thermal efficiency (ITE) increase under various working conditions. Among them, the MPRR increases by 9%–12%, while the ITE increases by 6%–7%. In terms of emissions, the nitrogen oxide (NOX) decreases obviously (decrease by 32%–54%), while the carbon monoxide (CO) and the hydrocarbons (HC) decrease slightly (CO: decrease by 4%–10%, HC decrease by 3%–4%).