LNG接收站利用低品位热源低温发电

LNG接收站需要大量的热能来加热气化LNG,降低燃气消耗可以减少操作费用。LNG接收站也要消耗大量的电能(2.83×107m3/天的气化量需要20～30MW)。利用LNG冷能低温发电能够显著减少操作成本,降低污染排放。采用中间流体Rankine循环的LNG低温发电流程,既可以生产电能,又可以输出指定温度下的产品天然气。该方案可以利用任何形式的低品位热源来气化LNG。模拟结果显示,气化容量为3.68×107m3/天的LNG接收站的低温发电系统,发电量为18MW,能带来每年0.7～1亿元的收益。     

具有纵向辅助耗尽衬底层的新型横向双扩散金属氧化物半导体场效应晶体管

为了优化横向双扩散金属氧化物半导体场效应晶体管(lateral double-diffused MOSFET,LDMOS)的击穿特性及器件性能,在传统LDMOS结构的基础上,提出了一种具有纵向辅助耗尽衬底层(assisted depletesubstrate layer,ADSL)的新型LDMOS.新加入的ADSL层使得漏端下方的纵向耗尽区大幅向衬底扩展,从而利用电场调制效应在ADSL层底部引入新的电场峰,使纵向电场得到优化,同时横向表面电场也因为电场调制效应而得到了优化.通过ISE仿真表明,当传统LDMOS与ADSL LDMOS的漂移区长度都是70μm时,击穿电压由462 V增大到897 V,提高了94%左右,并且优值也从0.55 MW/cm~2提升到1.24 MW/cm~2,提升了125%.因此,新结构ADSL LDMOS的器件性能较传统LDMOS有了极大的提升.进一步对ADSL层进行分区掺杂优化,在新结构的基础上,击穿电压在双分区时上升到938 V,三分区时为947 V.     

Frequency and intensity readouts of micro-wave electric field using Rydberg atoms with Doppler effects

A scheme of electric-field measurement of micro-waves is proposed in Rydberg atoms with Doppler effects. A cascade-type electromagnetically-induced-transparency (EIT) system is disturbed by a perturbative field coupling a metastable transition. The original dark state splits and two EIT window appear with a central absorption peak. When a micro-wave (MW) field couples the Rydberg transition, the central absorption peak is divided into two. The frequency splitting of two central peaks is proportional to the MW field intensity, which can be used to probe MW electric field strength. This frequency-readout method based on a double-dark state system increases the probe sensitivity nearly by a factor of 7, compared with that of the single-dark state case. At room temperature, Doppler effects can enhance the absorption spectrum, moreover, its peak value varies linearly with the MW field strength. This can also serve to measure MW electric field strength. Numerical results show that the latter intensity-readout method after Doppler averaging improves the probe sensitivity by a factor of 10 with respect to the case without Doppler effects.     

Frictional accumulation of negative muons and its application

A novel method is proposed for the efficient conversion of intermediate energy negative muons into a low-energy muon beam. It is based on using an electric field to eject muons from a moderator consisting of a large number of thin carbon foils placed perpendicularly to the axis of a high-field solenoid. High-energy muons are made to slow down within the moderator to an energy where further slowing down is inhibited by the electric field acceleration between the foils. The muons accumulate at low energy within the moderator hopping from one foil to the next until they come out as a low-energy muon beam. The resulting phase compression factor exceeds 1000. Efficient initial injection of the muons into the moderator is obtained either by letting the muons enter it in a direction opposite to the acceleration force or by producing the muons within a magnetic trap containing the moderator. A practical configuration based on the second scheme is presented. By implementing the method into the most intense muon production configurations a new pathway is opened that may ultimately compete with other schemes in the selection of the optimal source for high-energy muon colliders.     

A case study of cogeneration for Jeddah and Yanbu petromin refineries in Saudi Arabia

The Petromin refineries in Jeddah and Yanbu, Saudi Arabia produce power and process steam separately. The Jeddah refinery gas turbines that have an installed capacity of 88 MW, run at less than 50% utilization factor. The refinery demand of steam is 70–120 tons h⁻¹.The electric power demand of Yanbu refinery is supplied by The Royal Commission of Yanbu at a rate of 16–25 MW. The steam consumption is 68 tons h⁻¹. Data were collected for the performance and requirement for both plants. An integrated system for cogeneration is proposed which consists of a gas turbine, heat recovery steam generator equipped with a supplementary duct burner and economizer. The thermal and economical analyses have proved the feasibility of the proposed system with payback periods of 23 and 36 months for Jeddah and Yanbu refineries, respectively. However, the payback period for Jeddah refinery can be reduced to 15 months if the utilization factor is improved, and the excess power generated by the gas turbines is connected to the public utility grid. In fact, it is worth mentioning that the present study is considered the first to be carried out in Saudi Arabia; more studies and investigations could lead to tremendous saving in the fuel consumption in this country.     

强流脉冲下重复滑动电接触界面的电热特性

固体电枢电磁轨道发射中,膛内枢轨滑动电接触的电热特性关系到滑动界面的接触状态、电流传导品质和界面能量耗散,制约着系统效率和轨道寿命。设计开展了多组不同电流线密度的多发重复试验,通过采集电气试验数据进行迭代计算,得到了滑动接触电阻和界面焦耳热耗散功率的动态变化规律,分析了沉积物随重复发射的演变及电流线密度对电热特性的影响规律,并结合试验后轨道表面熔蚀沉积检测,讨论了滑动电接触界面的演变过程。结果表明:接触电阻稳定临界点和焦耳热耗散功率峰值点都出现在脉冲电流下降沿,接触电阻稳定值量级为10-2 mΩ,焦耳热功率峰值幅值可达10-1 MW;炮口速度随重复次数的增加而降低并趋于稳定,多次重复发射对滑动接触电阻和焦耳热功率较小的影响表明沉积物在发射中再次熔融并对电接触起积极作用;而即使输入能量一致,电流线密度的变化也显著影响了界面焦耳热的生成。     

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The structure principle, circuit model and application of the super capacitor were introduced in tokamak experiment. The arc discharge power supply characteristics of high power ion source and the circuit topology of 1MW NBI arc supply for HL-2A tokomak are comprehensively analyzed. An arc discharge power supply circuit for 5MW NBI ion source has been developed by application of super capacitors, which can reduce the load of electric network and has smaller size, higher efficiency, simpler control and quicker response speed. A scheme for 5MW NBI ion source filament power supply using super capacitors supply and constant voltage control has been put forward, and the feasibility and technical advantages of the scheme have also been given. To equalize the voltages of individual super capacitor in energy storage by a numerous super capacitors in series and in parallel, this paper put forward a reliable and efficient voltage balancing circuit.     

Design of high-average-power near-millimeter free electron laseroscillators using short period wigglers and sheet electron beams

The design and feasibility of a 1-MW continuous-wave (CW) free electron laser (FEL) oscillator are reviewed. The proposed configuration includes a short-period (I_w~ 1 cm) planar wiggler, a sheet electron beam, a 0.5-1.0-MV thermionic electron gun, a hybrid waveguide/quasi-optical resonator, commercial DC power supplies, and a depressed collector. Cavity ohmic RF losses are estimated to be extremely low (⩽10-100 W/cm²) at 1/MW output power, while thermal heat transfer studies conservatively indicate that wall cooling up to 1500 W/cm² should be possible. Experiments have convincingly verified theory and simulations which predict that negligible body currents will be achievable with low-emittance low-space-charge sheet beams. High-voltage sheet beam gun design studies indicate that the required beam quality can be achieved with CW compatible devices. The spent beam energy distribution is consistent with highly efficient spent beam energy recovery, and the proposed resonator cavity should provide mode discrimination and beam/RF separation capability     

Loop thermosiphon thermal collector for waste heat recovery power generation

A loop thermosiphon thermal collector was developed for the waste heat recovery power generation with electric capacity of 500 W. The heat collector with heat transfer area of 0.159 m² (500 mm width and 300 mm depth) was connected to the condenser with a shrunken heat transfer area by a loop. The thermal performance of the apparatus was declined when increasing the water filling rate to 90% as the working fluid occupied the internal volume. In the range of water filling rate between 30% and 60%, the effective thermal conductivity was around100 times of the conductivity of copper.     

超级电容在中性束弧放电电源中的应用研究

介绍了超级电容的结构原理与电路模型,以及超级电容在托卡马克装置实验中的应用。综合分析了大功率离子源弧放电电源的供电特性以及HL-2A 装置1MW 中性束注入系统的弧电源供电电路拓扑。提出了一种基于超级电容储能的5MW 中性束注入离子源弧放电电源供电方案,它能减小所需的电网容量,具有更小的体积和更高的效率、控制简单、响应速度快等特点。提出了采用恒压控制方式的基于超级电容供电的5MW 中性束注入离子源灯丝电源方案,分析了该方案的可行性和技术优势。为均衡用许多超级电容串并联组合储能时单体超级电容的电压,提出了一种可靠、高效的电压均衡电路。     

三阴极强流加速器研制

 研制了一台能同时产生3电子束的高功率强流加速器,该加速器主要由初级储能部分、线绕式脉冲变压器、水介质形成线和三阴极二极管组成,3根阴极分别伸入3个独立的漂移管,对3个电子束之间相互作用的电磁力起屏蔽作用。当该加速器二极管接单个阴极时,产生的电功率超过50 GW;当该加速器二极管同时接3个阴极时,产生3个电子束的电功率分别超过10 GW;当该加速器被用于驱动3个高功率微波管时,能产生L波段1.0 GW,S波段1.0 GW和C波段300 MW的微波输出。     

Power and heat fluctuation theorems for electric circuits

Using recent fluctuation theorems from nonequilibrium statistical mechanics, we extend the theory for voltage fluctuations in electric circuits to power and heat fluctuations. They could be of particular relevance for the functioning of small circuits. This is done for a parallel resistor and capacitor with a constant current source for which we use the analogy with a Brownian particle dragged through a fluid by a moving harmonic potential, where circuit-specific analogs are needed on top of the Brownian-Nyquist analogy. The results may also hold for other circuits as another example shows.     

基于RLCπ型等效模型的互连网络精确焦耳热功耗计算

基于互连网络的RLC π型等效模型,考虑电感的屏蔽作用和非理想的阶跃激励,提出了互连线网络在斜阶跃激励下的焦耳热功耗计算方法,极大地简化了互连网络中电流和功耗的表达式. 基于90 nm金属氧化物半导体(CMOS)工艺的互连参数对所提出的计算方法进行了计算和仿真验证,对于上升信号小于1 ns的情况,计算结果与Hspice仿真结果的误差小于3%,具有很高的精度,适合应用于大规模互连网络中的功耗估算和热分析.     

高功率微波效应的多层次多物理场协同算法

针对半导体器件、电路、电子系统的高功率微波效应,提出了一套全新的多层次多物理场协同计算方法。该算法基于半导体器件的物理结构模型,联立并求解由电磁场、半导体物理和热力学方程构成的多物理场方程组,实现了器件级高功率微波效应的仿真;通过器件多物理场仿真和电路仿真的协同计算完成电路级效应仿真;最后进行电路效应和电磁环境的协同计算,获取由多个电路、外壳封装、孔缝和线缆等组成的电子系统的高功率微波效应数据。介绍了该算法的原理和流程,以商业PIN二极管为例,计算了该器件及组成限幅器电路的温度效应、正向恢复特性、半封闭腔体内空间微波辐射等效应,通过与实验测试的对比验证了算法的正确性,同时对效应现象给出了物理机理解释。     

Gas turbine waste heat recovery distillation system

This article presents a method for improving the gas turbine's performance through an efficient utilization of the waste heat in a distillation system with a special arrangement. This consists of two trains of VTE/MEB connected to increase the fresh water produced. Exhaust gases from the gas turbine are used in a multi-temperature level heat recovery system with five feed heaters, and gases are released to ambient at 130°C. Distillation top train has nine effects and evaporation range from 130 to 82°C while the bottom train has six effects with evaporation range from 76 to 46°C and is supplied with the steam leaves the last effect in the top train.Thermal analysis using a 32.67 MW gas turbine showed that the present arrangement can produce 3.2 million gallons per day (mgd) of fresh water with more than 4 g/kWh at a performance ratio (PR) of 8.8. This is 34% more than that produced in an existing gas-turbine distillation combination and 14% more than that expected from a reverse osmosis plant driven by a bottoming Rankine power cycle.     

Optimization and Comparing a Different Various of Head Part of a Moderator of “Central” Direction for IBR-2 Reactor

The performance of the upstream moderator for neutron beams 1, 4, 5, 6, and 9 extracted from the IBR-2 reactor is simulated towards selecting its optimum configuration. For different moderator options, gain factors with respect to the existing comb-shaped water moderator are computed. Taking into account the technological issues in manufacturing a combined moderator, the scheme with optimal physical characteristics is selected.     

ELECTRIC CIRCUIT DESIGN AND TESTING OF INTEGRATED DISTRIBUTED STRUCTRONIC SYSTEMS

Modelling distributed parameter systems (DPS) by electric circuits and fabricating the complicated equivalent circuits to evaluate system responses poses many challenging research issues for many years. Electrical modelling and analysis of distributed sensing/control of smart structures and distributed structronic systems are even scarce. This paper is to present a technique to model distributed structronic control systems with electric circuits and to evaluate control behaviors with the fabricated equivalent circuits. Electrical analogies and analysis of distributed structronic systems is proposed and dynamics and control of beam/sensor/actuator systems are investigated. To determine the equivalent circuits and system parameters, higher order partial derivatives are simplified using the finite difference method; partial differential equations (PDE) are transformed to finite difference equations and further represented by electronic components and circuits. To provide better signal management and stability, active electrical circuit systems are designed and fabricated. Electrical signals from the distributed system circuits (i.e., soft and hard) are compared with results obtained by the classical theoretical, finite element, and experimental techniques.     

采用复合吸附剂多功效热管型吸附制冷机

设计制造了一台采用复合吸附剂(氯化钙和活性炭)-氨工作对的双床多功效热管型吸附制冷机,并进行了大量实验,获得了新型热管型吸附制冷系统的制冷特性。本系统分别采用丙酮或水为热管工作液,以加热器加热来模拟渔船余热加热。实验得出渔船制冰工况和船舶空调工况下的单位质量吸附剂的制冷功率SCP和制冷系统COP。结果显示水热管工质更适合于船舶余热应用。     

Enhancing gas turbine performance by intake air cooling using an absorption chiller

The performance of gas turbines, operated either as a simple cycle or a combined cycle, is critically constrained by the prevailing ambient temperature, particularly in arid and tropical climates. This paper investigates the option of cooling the intake air to the compressor of the gas-turbine system using an absorption chiller in order to increase the gas turbine capacity. High-temperature waste heat from the exhaust gas may be utilized to produce steam in a recovery boiler. Part of the steam produced could then be used to drive a lithium-bromide double-effect absorption chiller which in turn could cool the incoming air. An analysis carried out by taking the weather data of Bangkok (Thailand) indicates that reducing the temperature from ambient condition to 15°C could help to increase the instantaneous power output between 8 and 13%. As an outcome, as much as 11% additional electricity could be generated from the same gas turbine power plant.A simple economic assessment indicates that the proposed scheme will require a minimal investment as compared to the commissioning cost of a new gas turbine unit to meet the corresponding capacity increment. The latter will need nearly four times higher initial cost than the amount estimated for the proposed scheme. Thus, implementation of such a system would significantly abate the negative impact of the ambient temperature, while providing an economically and environmentally attractive option for energy producers in most developing nations of the world which are located in arid and tropical zones.     

High-power X-band amplification from an overmodedthree-cavity gyroklystron with a tunable penultimate cavity

Experimental results for a 10 GHz TE₀₁ mode three-cavity gyroklystron with a tunable penultimate cavity are presented. The electron beam was produced by a pulse line modulator and a magnetron injection gun which operates to 433 kV and 225 A with 1 μs flat-top. Three-cavity circuits have produced a peak power of 27 MW with efficiency of 32% and pulse energy of 39 J. A maximum gain of 50 dB was achieved at a peak power of 20 MW, and a maximum efficiency of 37% was achieved at a peak power of 16 MW