جستجوی مقالات مرتبط با کلیدواژه "turbine" در نشریات گروه "مکانیک"

Turbofan engines have attracted a lot of attention due to their high propulsion power. Compatibility of the simultaneous operation of the two main components of the turbofan engine, i.e., compressor and turbine, is one of the main concerns of designers and manufacturers. Because the form of characteristic curves of turbine and compressor are different and almost contradictory and will cause stagnation. In order to prevent turbofan surge, determining the matching of different components of this type of motors has become very important. The sensitivity of different parameters in the design of these types of engines is very high and achieving precalculated simulations that can have less calculation error will reduce the cost and time of the design stage. In this research, a lowerror simulation is designed to calculate the matching line of turbofan engines. In the stages of this research, first, the parameters affecting the matching line have been determined, and the method of calculating it has been extracted and simulated. Validation has been done for this simulation using the specifications of the RR-Trent 772-60, PW-PW4098 engines. According to the experiment performed, the thrust fuel consumption has been calculated with an error accuracy of less than 0.05 and the amount of thrust for different engines is less than 2000 (lbs). In another experiment, the correctness of determining the matching line for different components of the turbofan engine has been confirmed using the available resources. On the other hand, the accuracy of the overlap of the matching line of the simulation is 92% for the RR-Trent 772-60 engine and 94.2% for the PW-PW4098 engine.

Using twin web disks instead of single disks in turbine rotor is the new idea, which provides the necessary space for cooling and thus reducing the temperature level and the resulting stresses. The disk is subject to mechanical and thermal loading. Mechanical loading involves the effect of the disk rotation and the centrifugal load caused by the blade rotation at the external surface. Thermal loading is applied due to thermal changes between the internal and external surfaces on the disk. Disk boundary conditions are considered as dual-cantilever. Using the analytical solution method, the theory of elasticity of the plate is derived from the relations that govern the thickness of a rotating disk in a plane stress state. In the following, the disk was analysed under consideration the actual thickness profile using the TimoshenkoGrameel’s numerical method. In order to reach a twin web disk with a proper profile, this disk is studied with stepped holes in 400 different geometrical modes, and the state with the lowest possible mass and acceptable reliability coefficient is obtained. The results of the analysis show the reduction of mass, reduction of stress levels and improvement of the coefficient of confidence through the use of an optimal twin web disk.

The proper design of the stator turbine supercharger is of great help in increasing its performance and overall engine efficiency. In this research, with the help of FLUENT software, the local entropy generation and rate of exergy destruction of the turbine stator vane has been investigated. In the analysis, local entropy generation is divided into two sections: viscous entropy generation and thermal entropy generation, and the governing equations are defined with the help of UDF within the FLUENT software. After calculating the local entropy generation and determining the value of irreversibility quantities, According to the Gouy-Stodola equation, the amount of exergy destruction is calculated by numerical method. The results show that the two models of the Spalart Allmaras and k-ω(SST) have performed the best prediction wake of the vane. The amount of viscous entropy generation and thermal entropy generation is 69% and 31%, respectively. The values of the local entropy production calculated with the results of a stator turbine vane of authentic paper are validated with acceptable adaptation in it. The calculated exergy destruction is 281 kW, located in the range of modern gas turbines for a high-pressure turbine stage.

Nowadays, with regard to the reduction of fossil fuels and the management of their use, wind power is now rising as one of the most efficient renewable energy sources. Moreover, wind farms, which include sets of turbines in a vast farm, have become more developed and their designs and optimizations have risen recently. In this paper, the wind turbines are located in the wind farm and the effects of their positions and arrangements on the production power of the whole system are investigated. For this purpose, a square farm is considered and, having information on how the winds and wind speeds in each case (based on the Weibull distribution function), will extract the optimum location of wind turbines in the farm using optimization algorithms. The main goal of this research is to increase the total amount of power extracted from the wind farm based on the changes in the locations and arrangements of the turbines. This optimization problem is subjected to some constraints, such as the maximum number of turbines in the farm, the minimum distance between turbines and the overall size of the farm. To solve this optimization problem, the GA and PSO algorithms are used and the results of these methods are compared. The results of this study indicate that the power produced from all the turbines located in the wind farm has increased compared to previous works.