ABSTRACT In this article, to investigate the comprehensive influence of opening size and location packing box on precooling performance, a simulation model with 20 parameters is established based computational fluid dynamics. There are six openings one side box, 12 in total, 5 positions (Cases 1–5) 4 sizes, each an corresponding total area 15 mm (2120 2 ), 30 (8482 45 (19,085 60 (33,929 ). The results show that when diameter 15–60 mm, increasing increases time, Case 4, which moves position...

High-precision relative-state measurement technology is one of the key technologies for achieving precision formation flying distributed spacecraft. This paper conducts a comprehensive analysis formation-flying projects spacecraft in various countries. In context practical application, specific mission configuration, orbit distribution, technology, and payload project are summarized. On this basis, relative state techniques outlined first time, using non-autonomous techniques, autonomous new...

Precipitation-hardened Al–Si 356 cast alloys are widely used in fabricating the automotive engine parts due to their excellent castability and strength/weight ratio. However, with increasing demand of service temperature at 250–350°C, mechanical properties greatly deteriorate owing rapid coarsening precipitates elevated temperatures. In this study, individual combined transition elements (V, Zr Mo) were introduced into type form thermally stable dispersoids, influences on strength creep...

The definition of a good indoor climate is important to the success passenger rail coach, not only because it will decide its energy consumption and thus influence sustainability but also comfort for long journeys essential. A survey in coach investigating thermal air quality environment was undertaken. intention use results optimise control ventilation system provide an that passengers find comfortable. Field surveys were carried out long–haul sleeper cars China under real travelling...

The optical pyrometer is a widely used instrument for measuring the temperature of gas turbine blade targets. However, one limitations this measurement error caused by reflected radiation from high-temperature surrounding environment. This paper presents an analysis such with consideration wavelength detection range 2.5 to 22 μm thermal barrier coatings (TBCs) ranging 18 279 μm. Surface distributions were simulated using software ANSYS CFX. Radiation heat transfer was calculated based on...

Flameproof enclosures are widely installed as safety equipment at dangerous industrial sites to reduce ignition risks. However, electrical components typical?ly in such flameproof for the production process can cause and compromise of enclosures. Thus, cases, explosive characteristics is severely affected. Acci?dental gas explosions rarely occur under standard operating conditions. Premixed shells complex processes. A 560 mm ? 400 280 enclosure commonly used was investigate phenomenon. The...

The development of irradiation processing industry brings about various types objects and expands the requirements for better uniformity larger areas. This paper proposes an innovative design a permanent magnet electron beam spread system. By clarifying its operation principles, author verifies feasibility application in accelerators industrial use with examples energy ranging from 300 keV to 1 MeV. Based on finite element analyses electromagnetic fields charged particle dynamics, also...

To simulate the complex accident phenomena of a marine reactor, thermal-hydraulic system code RELAP5 is modified to perform analysis under ocean conditions. An integrated reactor with passive residual heat removal (PRHRS) modeled by improved code, and effects different motions total loss-of-flow (LOFA) loss-of-heat-sink (LOHS) are analyzed respect safety characteristics. The results indicate that for LOFA, primary loop can form an effective natural circulation cool core, LOHS, PRHRS...

With more and stringent requirements of large number connections high scalability in the next generation wireless network, a novel multiple access method, pattern division (PDMA), has become one promised technologies provides higher efficiency spectrum resource utilization. In this work, we propose joint allocation traffic offloading scheme PDMA-based satellite/terrestrial network. The proposed algorithm is based on two convex optimization methods, which iteratively solves splitting...

In view of the flight theory rotorcraft, breakthroughs in field rotorcraft configuration during recent twenty years are described this paper. From traditional (including single main rotor with tail rotor, tandem rotors, side by twin coaxial rotors and crossing rotors) to ones ducted non-tail helicopter, hingeless bearingless tilt-rotor, tip-jet reverse velocity system, compound helicopter rotor/wing transition helicopter), great progress on have been revolutionarily made. These new...

UAV networks often partition into separated clusters due to the high node and link dynamic. As a result, network connectivity recovery is an important issue in this area. Existing solutions always need excessive movement of nodes thus lead low efficiency terms time energy consumption. In paper, we for first study how utilize cooperative communication technology improve networks. We propose Cooperative Communication based Connectivity Recovery algorithm Networks, named C3RUN. The key novelty...

Offshore nuclear small reactor is a promising research direction during recent years. In order to carry out system simulation and safety analysis under accident conditions for marine reactors, the classic thermal-hydraulic code RELAP5 modified by taking heaving, inclining rolling motion into consideration in this paper. Additional forces are added momentum equation heaving rolling, control volume coordination transformed rolling. Then, simplified with two loops simulated effect of ocean...