scholarly journals A Model of Convex Programming for Turbojet Main Parameter Selection Optimization

1974 ◽  
Author(s):  
C. Turcanu
Keyword(s):  
Convex Programming ◽  
Main Parameter ◽  
Programming Model ◽  
Calorific Value ◽  
Combustion Efficiency ◽  
Parameter Selection ◽  
Maximum Temperature ◽  
Engine Operation ◽  
Operation Conditions ◽  
Specific Thrust

A mathematical modeling of well-known methods used to define turbojet main parameters aiming at solution optimization is described. The parameters considered include: compression ratio, maximum temperature for turbine, compressor efficiency, turbine efficiency, etc. By using the relationships for specific thrust, specific fuel consumption, etc., and assuming that construction and functional parameters such as calorific value, combustion efficiency, flight altitude and speed, etc., are known a function representing a sum of the ratios describing specific thrust and SFC deviations against maximum specific thrust and minimum SFC, respectively, is derived. Main parameter selection criteria pending on engine operation conditions and aircraft category are introduced. Mathematic analysis for main parameter selection optimization leads to a convex programming model for which both the function and the constraints are convex functions defined by convex fields. Although this paper makes reference to classic jet engines the method may be easily developed for by-pass engines, etc.

scholarly journals Diesel Engine Optimization for Electric Hybrid Vehicles

2009 ◽  
Vol 131 (1) ◽  
Author(s):  
Talal F. Yusaf
Keyword(s):  
Diesel Engine ◽  
Maximum Temperature ◽  
Exhaust Emission ◽  
Oxides Of Nitrogen ◽  
Engine Operation ◽  
Performance And Emission ◽  
Operation Conditions ◽  
Lubricant Oil ◽  
Emission Testing ◽  
Engine Life

Performance and emission testing for a single cylinder four-stroke diesel engine have been experimentally performed to determine the optimum operation conditions for this engine when it is used as a hybrid power unit. The studied operation parameters included brake specific fuel consumption (BSFC), exhaust emission (NOx, CO, CO2, and O2), and engine life. The results indicate that the lowest BSFC of the engine was found when the engine runs around 1 kW charging load at speed ranged between 1900 rpm and 2700 rpm. As the speed of the engine is maintained constant, the minimum level of BSFC is below 300 g/kW h at around 1900 rpm. The best engine operation conditions, for low emission, are found at engine speed around 2500 rpm. It was found that the oxides of nitrogen remain within the acceptable level (below 180 ppm) for such a diesel engine. The battery charge has been conducted at constant speeds, where the lubricant oil temperature was constant and always below maximum temperature; this is a good indication for longer engine life.

Modeling and Experiment on Combustion Characteristics for Biomass Rotary Burner

2020 ◽  
Vol 04 ◽  
Author(s):  
Guohai Jia ◽  
Lijun Li ◽  
Li Dai ◽  
Zicheng Gao ◽  
Jiping Li
Keyword(s):  
Combustion Chamber ◽  
Combustion Temperature ◽  
Combustion Efficiency ◽  
Middle Part ◽  
Combustion Characteristics ◽  
Maximum Temperature ◽  
Excess Air ◽  
Element Simulation ◽  
Excess Air Coefficient ◽  
Secondary Air

Background: A biomass pellet rotary burner was chosen as the research object in order to study the influence of excess air coefficient on the combustion efficiency. The finite element simulation model of biomass rotary burner was established. Methods: The computational fluid dynamics software was applied to simulate the combustion characteristics of biomass rotary burner in steady condition and the effects of excess air ratio on pressure field, velocity field and temperature field was analyzed. Results: The results show that the flow velocity inside the burner gradually increases with the increase of inlet velocity and the maximum combustion temperature is also appeared in the middle part of the combustion chamber. Conclusion: When the excess air coefficient is 1.0 with the secondary air outlet velocity of 4.16 m/s, the maximum temperature of the rotary combustion chamber is 2730K with the secondary air outlet velocity of 6.66 m/s. When the excess air ratio is 1.6, the maximum temperature of the rotary combustion chamber is 2410K. When the air ratio is 2.4, the maximum temperature of the rotary combustion chamber is 2340K with the secondary air outlet velocity of 9.99 m/s. The best excess air coefficient is 1.0. The experimental value of combustion temperature of biomass rotary burner is in good agreement with the simulation results.

scholarly journals A Review on the Thermochemical Recycling of Waste Tyres to Oil for Automobile Engine Application

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3837
Author(s):  
Mohammad I. Jahirul ◽  
Farhad M. Hossain ◽  
Mohammad G. Rasul ◽  
Ashfaque Ahmed Chowdhury
Keyword(s):  
Diesel Engine ◽  
Engine Performance ◽  
Calorific Value ◽  
High Viscosity ◽  
Combustion Efficiency ◽  
Fuel Additive ◽  
Pyrolysis Oil ◽  
Performance And Emission ◽  
Automobile Engines ◽  
Direct Use

Utilising pyrolysis as a waste tyre processing technology has various economic and social advantages, along with the fact that it is an effective conversion method. Despite extensive research and a notable likelihood of success, this technology has not yet seen implementation in industrial and commercial settings. In this review, over 100 recent publications are reviewed and summarised to give attention to the current state of global tyre waste management, pyrolysis technology, and plastic waste conversion into liquid fuel. The study also investigated the suitability of pyrolysis oil for use in diesel engines and provided the results on diesel engine performance and emission characteristics. Most studies show that discarded tyres can yield 40–60% liquid oil with a calorific value of more than 40 MJ/kg, indicating that they are appropriate for direct use as boiler and furnace fuel. It has a low cetane index, as well as high viscosity, density, and aromatic content. According to diesel engine performance and emission studies, the power output and combustion efficiency of tyre pyrolysis oil are equivalent to diesel fuel, but engine emissions (NOX, CO, CO, SOX, and HC) are significantly greater in most circumstances. These findings indicate that tyre pyrolysis oil is not suitable for direct use in commercial automobile engines, but it can be utilised as a fuel additive or combined with other fuels.

Estimation of the Occurrence of Micro-Explosion for the Diesel-Biofuel Multi-Components Droplets

2012 ◽  
Author(s):  
Cai Shen ◽  
Chia-fon F. Lee ◽  
Way L. Cheng
Keyword(s):  
Surface Energy ◽  
Minimal Surface ◽  
Weber Number ◽  
Numerical Study ◽  
Engine Operation ◽  
Fuel Droplets ◽  
Fuel Blends ◽  
Operation Conditions ◽  
Simulation Results ◽  
Breakup Model

A numerical study of micro-explosion in multi-component bio-fuel droplets is presented. The onset of micro-explosion is characterized by the normalized onset radius (NOR). Bubble expansion is described by a modified Rayleigh equation. The final breakup is modeled from a surface energy approach by determining the minimal surface energy (MSE). After the breakup, the Sauter mean radius (SMR) for initially small size droplets can be estimated from a look-up table generated from the current breakup model. There exists an optimal droplet size for the onset of micro-explosion. The MSE approach reaches the same conclusion as previous model determining atomization by aerodynamic disturbances. The SMR of secondary droplets can be estimated by the possible void fraction, ε, at breakup and the corresponding surface Weber number, Wes, at the minimal surface energy ratio (MSER). Biodiesel can enhance micro-explosion in the fuel blends of ethanol and diesel (which is represented by a single composition tetradecane). The simulation results show that the secondary atomization of bio-fuel and diesel blends can be achieved by micro-explosion under typical diesel engine operation conditions.

Research on Application of Waste Plastic Disposal of Marine Diesel Engines

2008 ◽  
Vol 45 (04) ◽  
pp. 191-193
Author(s):  
Wei Hai-jun ◽  
Wang Guo-you ◽  
Wang Xiao-rui
Keyword(s):  
Diesel Engines ◽  
Calorific Value ◽  
Diesel Oil ◽  
Fuel Oil ◽  
Advanced Technique ◽  
Engine Operation ◽  
Waste Plastic ◽  
Marine Diesel ◽  
Points Of View ◽  
Research On Application

The purpose of this paper is to study the applicability of thermal processed fuel oil (hereafter called waste plastic disposal, or WPD) of diesel engines using low-quality fuel oil. In the experiment, stability of engine operation and components of exhaust gas, such as NOx and COx, were inspected from basic and applicable points of view. This paper illustrates a new test and result of WPD oil applied to marine diesel engines. In recent years, efforts have to be made to develop an advanced technique for recycling waste plastics in order to use scrapped plastics as fuel for diesel engines. It is very important and necessary for us to cope with the increasing calorific value and to satisfy the growing need of environment protection. The experimental fuel oil is obtained by a mixing of diesel oil, WPD, and water.

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