Influence Of Laser Cladding on Behavior of Fatigue and Fatigue Corrosion

Nickle based super alloys such as Inconel 600 are being extensively used to manufacture turbine blades for jet engines since their superior mechanical characteristics at higher working temps. The chemical composition of steam turbine blades show that is steel 52 it has a wide range of Energy, Tanks, Rail, Yellow Goods, Engineering, Bridges, Construction, applications. Laser cladding seems to be a surfacing method that uses lasers to improve the characteristics of a component’s surface and/or renew it. Laser cladding involves absorption of laser light that melts a small area of the substrates against which the substance was being introduced and fuses the coating substance to the substrates, resulting in the formation of a new layer. This research aims to investigate the fatigue and fatigue corrosion behavior of these turbine blades before and after exposure to laser cladding. The cladding process applied with this parameter Pulse energy = 11 joules, Pulse width = 6 Ms., Pulse frequency = 12 Hz, Laser Average Power = 132 W, Laser peak power = 1.83 KW. The results show, after cladding process the microstructure of the specimen is smooth and increase the cyclic of fatigue comparison with specimen without laser cladding process. So, the fatigue resistance is increased.

The jet fuels anti-wear properties indicator

There are three main fuel brands for jet engines of civil aviation used: domestic TS-1 and RT and foreign, produced in relatively small volumes in Russia, JET A-1 (JET A-1). Since the end of the 2000s, foreign manufacturers have made claims to the quality of the mass-used domestic fuel brand TS-1, and these claims have not been specified. However, the service life of a number of foreign engines operating on TS-1 fuel has been reduced by 50%. This circumstance can be caused by both subjective reasons – commercial and political interests of equipment manufacturers, and the objective ones. The main objective reason may be that recently several Russian plants producing TS-1 fuel have begun to produce composite propellant under the same name, where products of secondary oil refining processes are added to the straight-run fractions. These fuels meet the requirements of the standard (GOST 10227-86), which does not contain an indicator that characterizes the anti-wear properties of jet fuels. In the standard for JET A-1 fuel, anti-wear properties are normalized, and they are also normalized in the standard for domestic fuels for supersonic aviation. The article presents comparative tests of anti-wear properties of samples of jet fuels used in the civil aviation. The article substantiates the relevance of the anti-wear properties indicator in the standard for domestic brands of jet fuels for subsonic aircraft introduction, as well as the comparative analysis of the anti-wear properties of fuels produced by various Russian oil refineries. Indicators and methods for assessing the anti-wear properties of aviation fuels can be different. As such an indicator, it is proposed to use the anti-wear properties indicator calculated after testing fuel samples on a four-ball friction machine.

MODERN DREAMS. PLANNING FIREPLACES

An analysis of the current pace of development of hypersonic technologies for the means of launching spacecraft into Earth orbit, as well as for unmanned weapons systems, which embody both impact properties and reconnaissance functions. In order to better understand the strategic importance of technologies based on direct-flow jet engines, fragmentary coverage of the impressive path of achievements of aerospace technology, given some of the highlights of the history of its formation. The presented article analyzes the current problem - increasing the reliability, reliability and accuracy of the definition and classification of moving targets by autonomous means of aircraft on combat duty. The results of the research cover the features of the starting positions and functional action on the combat duty of aircraft of different classes and bases and are able to serve as a reliable scientific basis for improving military equipment on hypersonic technologies

Analysis of Energy Utilization and Losses for Jet-Propelled Vehicles

The global control volume-based energy utilization balance for an aerospace vehicle is extended to allow for the analysis of jet-propelled vehicles. The methodology is first developed for analyzing the energy utilization and entropy generation characteristics of jet engines without airframe considerations. This methodology, when combined with separate energy utilization analysis for an unpowered airframe, allows for the assessment of a powered vehicle. Wake entropy generation for a powered vehicle is shown to be the summation of the wake entropy generation associated with the propulsion system (no airframe) and the unpowered airframe. The fundamental relationship between overall entropy generation and the flight conditions required for maximum range and endurance of a powered vehicle are also derived. Example energy utilization results obtained for a modeled turbojet engine in off-design operation are provided; wake and engine component entropy generation characteristics are directly related to engine operation and flight conditions. This engine model is then integrated with a legacy (twin-engine) Northrop F-5E Tiger II airframe. The overall entropy generation temporal rate for the vehicle is minimized, as predicted by our analysis, at flight conditions corresponding to maximum endurance. For flight conditions corresponding to maximum range, the overall entropy spatial rate is minimized.

Use of the Method of Guidance by a Required Velocity in Control of Spacecraft Attitude

We apply the method of guidance by a required velocity for solving theoptimal control problem over spacecraft’s reorientation from known initialattitude into a required final attitude. We suppose that attitude control iscarried out by impulse jet engines. For optimization of fuel consumption,the controlling moments are calculated and formed according to themethod of free trajectories together with principle of iterative controlusing the quaternions for generating commands to actuators. Optimalsolution corresponds to the principle “acceleration - free rotation - separatecorrections - free rotation - braking”. Rotation along a hitting trajectory issupported by insignificant correction of the uncontrolled motion at discreteinstants between segments of acceleration and braking. Various strategies在自由运动阶段形成校正脉冲的方法是建议。提高实现航天器最终位置的准确性通过终端控制使用有关当前姿态的信息和用于确定开始时刻的角速度测量制动（根据实际运动参数开始制动的条件以分析形式制定）。所描述的方法是通用的并且相对于转动惯量不变。发展的态度法则控制涉及具有预测模型的算法，综合控制模式对于外部扰动和参数错误。数学建模的结果表明证明设计算法的实际可行性和高效率。

Weather Variability Induced Uncertainty of Contrail Radiative Forcing

Persistent contrails and contrail cirrus are estimated to have a larger impact on climate than all CO2 emissions from global aviation since the introduction of jet engines. However, the measure for this impact, the effective radiative forcing (ERF) or radiative forcing (RF), suffers from uncertainties that are much larger than those for CO2. Despite ongoing research, the so called level of scientific understanding has not improved since the 1999 IPCC Special Report on Aviation and the Global Atmosphere. In this paper, the role of weather variability as a major component of the uncertainty range of contrail cirrus RF is examined. Using 10 years of MOZAIC flights and ERA-5 reanalysis data, we show that natural weather variability causes large variations in the instantaneous radiative forcing (iRF) of persistent contrails, which is a major source for uncertainty. Most contrails (about 80%) have a small positive iRF of up to 20 W m−2. IRF exceeds 20 W m−2 in about 10% of all cases but these have a disproportionally large climate impact, the remaining 10% have a negative iRF. The distribution of iRF values is heavily skewed towards large positive values that show an exponential decay. Monte Carlo experiments reveal the difficulty of determining a precise long-term mean from measurement or campaign data alone. Depending on the chosen sample size, calculated means scatter considerably, which is caused exclusively by weather variability. Considering that many additional natural sources of variation have been deliberately neglected in the present examination, the results suggest that there is a fundamental limit to the precision with which the RF and ERF of contrail cirrus can be determined. In our opinion, this does not imply a low level of scientific understanding; rather the scientific understanding of contrails and contrail cirrus has grown considerably over recent decades. Only the determination of global and annual mean RF and ERF values is still difficult and will probably be so for the coming decades, if not forever. The little precise knowledge of the RF and ERF values is, therefore, no argument to postpone actions to mitigate contrail’s warming impact.

Application of Ultrasonic Atomization on a Micro Jet Engine Using Biofuel for Improving Performance

Jet engines are commonly used in aeronautical applications, and are one of the types of gas turbine engines. The circulation of air releases heat energy to expand the volume of hot fluids and impact the turbine wheel to generate power of hot gases. The present study investigates the potential of using ultrasonic atomization technology to assist in the combustion process. An experimental rig was set up to determine the performance of jet engines using ultrasonic droplets. A gas analyzer was used to measure various greenhouse emissions of exhaust gas. The performance of the engine was tested under three load levels (high, medium, low), starting from 10 psi at a steady state, to the minimum value. A significant result was tested for a low value of nitrogen monoxide at the three levels of load, and a specific result was tested for an efficiency value of 2% at the three levels of load. Carbon dioxide was found to decrease at the low load level. The use of an ultrasonic atomization device to assist in the combustion process was useful in achieving engine efficiency of 1% and a reduction of 25% in carbon dioxide exhaust gas.