javad zareei

In this paper, the effect of boundary layer excitation on increasing the heat transfer coefficient of water/carbon nanotube (CNT) nanofluid and water/aluminum oxide (Al2O3) nanoparticles has been investigated. The turbulent flow equations inside the pipe with RNG K-ε turbulence model are solved employing fluent software. The results show that the use of water/CNT nanofluid significantly increases the heat transfer coefficient of the convection. There is no such increase for water-aluminum oxide nanoparticles. If the volumetric percentage of the carbon nanotube increases, the rate of increase in the heat transfer coefficient and the flow pressure drop will increase. Therefore, the use of water/CNT nanofluid with lower volumetric percentages is better for improving the convective heat transfer. Also, by placing the barrier on the inner wall of the tube and stimulating the boundary layer, the heat transfer coefficient  thereafter increases in the excitement area. In the present study, the use of three obstacles behind each other has increased the average heat transfer coefficient by 16.7%.

Diesel engines are the most trusted sources in the transportation industry. They are also widely used in the urban transportation system. Most pollutants are related to these engines. Therefore, it is important to increase the performance and reduce exhaust emissions of these engines. Alternative fuels are key to meeting upcoming targets.
An experimental and numerical study was performed to investigate the effect of diesel fuel and hydrogen addition to diesel fuel from 0 to 30% on performance and exhaust emissions. Also in this research for changing diesel fuel, an indirect injection engine converted to direct injection engine. The simulation study was conducted by Star cd codes and experimental investigation was carried out on a diesel engine (Perkins 1103A-33TG1), three- cylinders, and four-stroke with maximum engine power 72.3hp at 1800 rpm. The results from this study showed that the increase of hydrogen to diesel fuel improves the thermal efficiency, resulting in lower specific fuel consumption. Also, the results showed that adding hydrogen until 30%, the cylinder pressure increase by about 9% and occurred the delay of peak pressure about 8 degrees of a crank angle compared to diesel fuel. The other obtained results in emission with 30%H2+Diesel showed the soot emission reduced 11.3%, HC and CO reduced nearly 36%, but NOx increased by about 8.3% due to high combustion temperature.

In internal combustion engines, the turbocharger and alternative fuels are two important factors affecting engine performance and exhaust emission. In this investigation, a one-dimensional computational fluid dynamics with GT-Power software was used to simulate a six-cylinder turbocharged diesel engine and the naturally aspirated diesel engine to study the performance and exhaust emissions with alternative fuels. The base fuel (diesel), methanol, ethanol, the blend of diesel and ethanol, biodiesel and decane was used. The results showed that decane fuel in the turbocharged engine has more brake power and torque (about 3.86%) compared to the base fuel. Also, the results showed that the turbocharger reduces carbon monoxide and hydrocarbon emissions, and biodiesel fuel has the least amount of carbon monoxide and hydrocarbon among other fuels. At the same time, the lowest NOX emission was obtained by decane fuel. As a final result can be demonstrated that the decane fuel in the turbocharged engine and the biodiesel fuel in the naturally aspirated engine could be a good alternative ratio to diesel fuel in diesel engines.

One of the main issues in internal combustion engines is the reduction of the flow of air into the cylinder and, consequently, the reduction of engine efficiency. To solve this problem, the turbocharger can be used as a proper device in diesel engines to increase the efficiency and performance of the engine. The turbocharger is located in the direction of the exhaust gases to compress the air during the process and direct it into the cylinders to increase the volumetric efficiency as well as more complete combustion to reduce the exhaust emissions. The simultaneous use of turbochargers and intercooler in diesel engines reduces the temperature of the intake air into the cylinder and increases the volumetric efficiency. In order to investigate the effect of turbocharger and intercooler on the operation of the Ferguson 285 engine, a turbocharger with intercooler was used and installed on the engine, and then required tests carried out by hydraulic dynamometer in different speeds of 1000, 1500, 2000 and 2500 RPM at full load. The results showed that the engine torque at different speeds in the presence of turbocharger and intercooler increases by 27.22%. The results also indicated that the installation of turbocharger and Intercooler on a diesel tractor is meaningful in %1 level at speeds of 1500 until 2500 RPM in this engine, so that the presence of a turbocharger and intercooler in the range above 1500 increase the engine performance. Also, the difference in temperature between the intercooler input and output shows that during higher speeds, the temperature difference is higher than the lower speeds, which contributes to the increase and improvement of engine volumetric efficiency. Also, the difference in temperature between the intercooler input and output shows that during higher speeds, the temperature difference is higher than the lower speeds, which contributes to the increase and improvement of engine volumetric efficiency.

Start of fuel injection and fuel type are two important factors affecting engine performance and exhaust emissions in internal combustion engines. In the present study, a one-dimensional computational fluid dynamics solution with GT-Power software is used to simulate a six-cylinder diesel engine to study the performance and exhaust emissions with different injection timing and alternative fuels. Starting the fuel injection was from 10 °CA BTDC to the TDC with an interval between two units and from alternative fuel bases (diesel), including methanol, ethanol, diesel, and ethanol compounds, biodiesel and decane was used. To validate the model, a comparison is made between simulation data and experimental data (including torque and power) showing the validation error is less than 6.12% and indicating the software model validation. Also, the modeling results show that decane fuel has higher brake power and brake torque of more than 6.10 % while fuel is injected at 10 °CA BTDC compared to the base fuel, and illustrates a reduction of 5.75 % in specific fuel consumption due to producing higher power. In addition, with the advance of injection timing compared to baseline, the amount of CO and HC in biodiesel fuel reduces to 83.88% and 64.87%, respectively, and the lowest NOX emission with the retardation of starting injection, to decane fuel is awarded. In general, the results show that decane fuel could be a good alternative to diesel fuel in diesel engines when it starts fuel injection at 10 °CA BTDC.

This study investigates the effect of compression ratio and different fuels on engine performance and exhaust emissions in a 6.8L turbocharged industrial diesel engine. For carried out this work, a 6 cylinder four stroke engine with gamma technologies power software is modelled and the effect of compression ratio (15:1 - 19:1) and alternative fuels (Diesel, Ethanol, Methanol, Decane, Soybean biodiesel, Diesel- Ethanol) at wide open throttle and various speeds from 800-2400 rpm are presented. The results indicate that the brake specific fuel consumptions of decane fuel at a compression ratio of 17:1 is lower than those of other fuels and also the maximum brake torque obtained with decane fuel at 1400 rpm. At this engine observed that decane fuel has higher brake power as compared to other fuels used due to higher heating value content. The emission results show that diesel fuel emitted more Carbon monoxide and Carbon dioxide emissions but soybean biodiesel (B100) has less Carbon monoxide, whereas highest oxides of nitrogen is founded with soybean biodiesel. Carbon monoxide and Carbon dioxide emissions are very close to each other when used decane and diesel fuel. In general decane fuel has higher performance and soybean biodiesel had fewer emissions at a compression ratio of 17:1.

Changing the compression ratio and presence of turbocharger are two important issues, affecting on performance, and exhaust emissions in internal combustion engines. To study the functional properties and exhaust emissions in regards to compression ratio at different speeds, the numerical solution of the governing equations on the fluid flow inside the combustion chamber and the numerical solution of one-dimensional computational fluid dynamics with the GT-Power software carried out. The diesel engine was with a displacement of 6.4 Lit and Turbocharged six-cylinder. In this engine was chosen, the compression ratio between 15: 1 and 19: 1 with intervals of one unit and the range of engine speed was from 800 to 2400 rpm. The results showed that by the presence of a turbocharger and changing the compression ratio from 17: 1 to 19: 1, the braking power and torque increased by about 56.24% compared to the non-turbocharged engine. In addition, was reduced the brake specific fuel consumption due to higher power output. The amount of CO and HC emissions decreases based on the reduction of the compression ratio compared to the based case, and the NOX value increases due to the production of higher heat than turbocharged engines. The overall results showed that the turbocharged engine with a 19: 1 compression ratio has the best performance and pollution characteristics.

Aim: In all societies, burn is a health cause’s physiologic mental economic and health disorder both for the patient and its family challenge and more than any other trauma. Cases such as lifestyle, social, economic, and cultural levels of society can change the type of burns. Given that data mining is growing and new, it is also of great importance to medical data. Therefore, in this project, the intention is to collect data using actual data mining techniques and in view of the prevalence of burns in developing countries, a model for establishing a meaningful relationship between the economic and social status of individuals develop burns as a result of their treatment.
The present study is analytic-descriptive based on retrospective nature. The population of the study consists of 553 patients all adult burn patients who were hospitalized in Ayatollah Taleghani hospital in Ahvaz for 3 years (1388-1390).data have been collected from check lists and questionnaire. The collected data were computed using spss22, IBM Modeler 14.2 and algorithm of C5.0, CHAID and CART.
The predicted model for the outcome of burn on patients conducted through selected algorithms in order of priority including factors of burn, occupation, capsule at home, place of incident, residential area, and rate of income, intent, gender and education.By comparing the accuracy of the algorithms, the highest accuracy is for the C & R algorithm (0.87), the most characteristic of the CHAID algorithm (0.98) and the most sensitivity was obtained for the C & R algorithm (0.50). Given the superiority of the C & R model, this model was recognized as the top model in terms of the accuracy and sensitivity of the models.
Due to the average accuracy of suggested models, these models are both valid and attributable. The results of this study can be useful for the prediction of the impact of socioeconomic factors on burnout outcomes.

The preparation of air–fuel mixture is considerably dependent on fluid flow dynamics to achieve improved performance, efficiency, and engine combustion in the appearance of flow. In this study, the effects of mixtures of hydrogen and compressed natural gas (CNG) on a spark ignition engine are numerically considered. This article presents the results of a direct-injection engine using methane–hydrogen mixtures containing H2 between 0% and 15% by volume. The result shows that the percentage of hydrogen in the CNG increases the burning velocity of CNG and reduces the optimal ignition timing to obtain the maximum peak pressure of an engine running with a blend of hydrogen and CNG. With hydrogen addition to natural gas, the peak heat release rates increase. For 15% hydrogen, the maximum values at crank angles (CAs) for in-cylinder temperature and heat release rate are achieved at 8° CA, and the maximum temperature is approximately 150 K. Port injection gasoline is converted into direct injection by CNG fuel in this engine.