关于汽轮机双撞击子机械超速保护系统的安装及故障分析

随着国家对火电机组"上大压小"政策的实施,200MW以下新装机组量骤减,除自备电厂和供热机组外已不再批准建设,导致200MW以下机组的安装技术出现断层,尤其是双撞击子机械超速保护系统的安装,因其系统和结构复杂,如在安装及检修过程中把关不严,在启动过程中将出现诸多问题,本文将结合个人经验阐述其安装注意事项及故障分析。

600MW机组危急遮断装置故障分析与处理

针对漳山发电厂3号机组在汽轮机定速喷油试验时不成功的情况,分析了危急遮断装置存在的问题,提出了针对性的解决方法,从而提高了整个危急遮断装置的安全稳定性。

危急遮断转速装置的校验研究

危急遮断器可防止汽轮机超速,准确、快速追忆汽轮机撞击子的机械飞出的瞬间实际转速,保证机组安全运行。对危急遮断转速装置的校验,应该模拟现场实际情况。为撞击子传感器安装提供可靠的理论依据,是我们迫切需要解决的问题。

A novel experimental system for performance evaluation of water powered percussive rock drill

A set of water powered excavation test system was developed for the comprehensive performance testing and evaluation of water powered percussive rock drill indoors. The whole system contains hydraulic power section, electronic control system, test and data acquisition system, and assistant devices, such as guideway and drilling bench. Parameters of the water powered percussive rock drill can be obtained by analyzing testing data, which contain impact energy, front and back cavity pressure, pressure and flow in each working part, drilling velocity, frequency and energy efficiency etc. The system is applied to test the self-designed water powered percussive rock drill SYYG65. The parameters of water powered percussive rock drill with impact pressure of about 8.9 MPa are 58.93 J for impact energy, and 8.97% for energy efficiency, which prove the effectiveness of system.

A molecular dynamics-based comparison of defect production in collision cascades during the bombardment of iron with different ions

We present a computer simulation study on the influence of incident ions on the energy transferred to primary knock-on atoms(PKAs)and defects produced in the cascade collision of irons.Three types of ions(H,Fe,and Xe,which are frequently used in irradiation experiments)with an energy of 3 MeV were simulated.According to the calculation results of SRIM,the average energy transferred to PKAs by Fe ions was the highest among the three types.Then,cascade collisions induced by PKAs with different energies were simulated by the molecular dynamics method.The maximum number of defects produced during irra-diation increased,and the time taken by defect number peak formation was extended with the increased energy of PKAs.The difference in radial distribution function between pre-and post-irradiation irons showed that a higher energy of PKA transferred resulted in a flatter curve.Besides,the law of defects varying in temperature was also investigated.All the researches imply that heavy ions can substitute for neutrons in irradiation experiments which is a practicable way,but the influence of conditions must be taken into account.

Energy-dissipative dual-crosslinked hydrogels for dynamically super-tough sensors

In the fields of electronic skin and soft wearable sensors,intrinsically stretchable conductors undergo rapid development;however,practical applications of artificial skinlike materials/devices have not been realized because of the difficulty in combining the electromechanical properties and sensing performance.Contrarily,insoluble inorganic conductive domains in the hydrogel matrix are generally incompatible with surrounding elastic networks,decreasing the mechanical strength.Usually,the hydrogels are vulnerable either to severe mechanical stimuli or large deformation,especially when notches are induced.In this study,based on an energy-dissipative dual-crosslinked conductive hydrogel,a mechanically durable and super-tough strain sensor was developed.The highly soft yet dynamically tough hydrogel demonstrated high ionic conductivity(30.2 mS cm^(-1)),ultrastretchability(>600%strain),and superior linear dependence of strain sensitivity with a maximum gauge factor of 1.2 at 500%strain.Because of these advantageous synergistic effects,the resultant hydrogel strain sensor demonstrated reliable and stable detection of a large range of human motion and subtle vibrations.Moreover,it impressively exhibited super toughness that could endure consecutive treading pressure and even retain normal operation after 20 times of car run-over on the road.These demonstrations highly confirm the sensor’s superior mechanical durability and reliability,displaying great potential in developing next-generation mechanically adaptable sensors.

Influence of mechanical damage generated by small space debris on electrostatic discharge

Recent studies have indicated that hypervelocity impacts by meteoroids and space debris can induce spacecraft anomalies. However, the basic physical process through which space debris impacts cause anomalies is not entirely clear. Currently, impact-generated plasma is thought to be the primary cause of electrical spacecraft anomalies, while the effects of impact-generated mechanical damage have rarely been researched. This paper presents new evidence showing that impact-generated mechanical damage strongly influences electrostatic discharge. Hypervelocity impact experiments were conducted in a plasma drag particle accelerator, using particles with diameters of 200–500 ?m and velocities of 2–7 km/s. The impact-generated mechanical damage on a specimen surface was measured by a stereoscopic microscope and 3D Profilometer and it indicated that microscopic irregularities around the impact crater could be responsible for local electric field enhancement. Furthermore, the influence of impact-generated mechanical damage on electrostatic discharge was simulated in an inverted potential gradient situation. The experimental results show that the electrostatic discharge voltage threshold was significantly reduced after the specimen was impacted by particles.