Centrifugal deformations of the gravitational kink

The Kaluza-Klein reduction of 4d conformally flat spacetimes is reconsidered. The corresponding 3d equations are shown to be equivalent to 2d gravitational kink equations augmented by a centrifugal term. For space-like gauge fields and non-trivial values of the centrifugal term the gravitational kink solutions describe a spacetime that is divided in two disconnected regions.     

The combined use of SCF-MO calculations and experimental data in the evaluation of quadratic force fields: MOCIC potential functions for fluoroform,methyl acetylene,and methyl cyanide

A semiempirical method combining SCF-MO calculations and limited vibrational data has been employed to evaluate the completely general quadratic potential fields of fluoroform, methyl acetylene, and acetonitrile. MOCIC (molecular orbital constraint using interaction coordinates) potential fields are presented for gas phase molecules of intermediate size. Here general harmonic force fields or excellent approximations utilizing extensive experimental data are available as standards. A statistical evaluation of the interaction potentials shows that there is some improvement in going from MNDO or ab initio SCF-MO force fields to the MOCIC functions which reliably reproduce the off-diagonal vibrational potential constants in most instances. The MOCIC primary compliants are excellent approximations of their vibrational counterparts, as expected. Comparison of the calculated isotopic frequencies, Coriolis coupling constants, and centrifugal distortion constants for the SCF-MO, MOCIC, and vibrational spectroscopic potential fields with the corresponding experimental values also shows MOCICs reliability for molecules with many interaction potentials. There is substantial improvement in the calculated isotopic frequency shifts and centrifugal distortion constants in going from SCF-MO to MOCIC functions.     

遗传算法在离心压缩机参数优化中的应用

遗传算法是当今世界上应用比较广泛的优化算法之一,特别是在处理有界多极值复杂函数方面有着明显的优势．在流体机械行业中,设计参数的优化问题往往涉及求解一些复杂隐函数在约束区间内的极值问题．因此将遗传算法应用到流体机械的设计参数优化当中有明显的现实意义．本文介绍了遗传算法在离心压缩机参数优化中的应用,并与传统的复合型法所获得的优化结果进行了比较,对比的结果显示出了遗传算法的优越性．     

封闭方腔热磁对流强化换热的实验研究

自然对流是由非保守体积力驱动的流体流动,这种体积力可以是重力、离心力以及电磁场力等;通过外加梯度磁场来影响流体的流动,产生强化换热效果的方法是一种新型的强化技术．本文利用永磁体产生0．3 g左右的加速度,采用马赫干涉仪对封闭方腔内空气的热磁对流的强化换热现象进行了实验研究,得到了温度场的干涉图像,并与理论模拟结果进行了比较,发现磁场对空气的自然对流换热有一定的强化作用．     

The radial force on a charged particle in superimposed magnetic fields on Schwarzschild spacetime

Following the approach of optical reference geometry we derive the expression for the total force in the radial direction acting on a charged particle in magnetic fields superimposed on the static Schwarzschild background and show the possible existence of bound orbits for particles in the field of ultra compact objects at distancesr?3m wherein the Lorentz force counterbalances both the gravitational and centrifugal forces.     

Rotary storage heat pump

This paper describes a chemical storage device combined with a vapour-recompression system designed to operate using the cheap rate “Economy 7” electricity tariff. The rotary storage device employs process intensification which exploits centrifugal fields. The heat pump uses exhaust air from a ventilation system, in which fresh air is supplied via a sunspace of a house, as its main heat source. The heat pump has been analysed thermodynamically using various refrigerant/absorbent combinations.     

Nonuniform elastomagnetoelectric effects in a disordered medium

A system of nonlinear equations for the determination of the ground state and the analysis of the possibility of the existence of different elastomagnetoelectric effects in the presence of nonuniform external influences has been obtained by the method of variation of the thermodynamic potential of the disordered medium over the electric and magnetic field strengths and elastic strains. It has been shown that the nonuniform strains created by the gravitational or centrifugal forces can serve as a source of the internal electric fields.     

Application of pressure sensitive paint measurement to a low-solidity cascade diffuser of a transonic centrifugal compressor

A pressure sensitive paint (PSP) measurement has been known as a pressure field measurement technique based on the oxygen quenching phenomenon of luminescence of specific luminophores. A PSP measurement was applied for pressure field measurement in a low-solidity circular cascade diffuser of a single-stage transonic centrifugal compressor with 5 in pressure ratio for HFC134a gas. The oxygen concentration was about 500 ppm. Ru (bath-phen) was adsorbed on a silica-gel thinlayer chromatography sheet, and the sheet was pasted onto the side-wall between the cascade vanes. A drastic change in luminescent intensity was recognized during a surge condition. Also the pressure variations based on luminescent intensity agreed well with the pressure fluctuations measured using a semiconductor pressure sensor with high-frequency-response. It was shown that a PSP measurement worked well to investigate the unsteady pressure fields in a circular cascade diffuser of a transonic centrifugal compressor. Moreover, the time response of PSP becomes clear as a problem to be overcome for the present.     

p-Wave Feshbach molecules

We have produced and detected molecules using a p-wave Feshbach resonance between 40K atoms. We have measured the binding energy and lifetime for these molecules and we find that the binding energy scales approximately linearly with the magnetic field near the resonance. The lifetime of bound p-wave molecules is measured to be 1.0+/-0.1 ms and 2.3+/-0.2 ms for the ml=+/-1 and ml=0 angular momentum projections, respectively. At magnetic fields above the resonance, we detect quasibound molecules whose lifetime is set by the tunneling rate through the centrifugal barrier.     

Gyroscopic Precession and Inertial Forces in Axially Symmetric Stationary Spacetimes

We study the phenomenon of gyroscopic precession and the analogues of inertial forces within the framework of general relativity. Covariant connections between the two are established for circular orbits in stationary spacetimes with axial symmetry. Specializing to static spacetimes, we prove that gyroscopic precession and centrifugal force both reverse at the photon orbits. Simultaneous non-reversal of these in the case of stationary spacetimes is discussed. Further insight is gained in the case of static spacetime by considering the phenomena in a spacetime conformal to the original one. Gravi-electric and gravi-magnetic fields are studied and their relation to inertial forces is established.     

Use ofD J,DJK constants for the unique fixing of intramolecular forces inXY 3 pyramidal molecules

A mathematical formalism is developed to evaluate all the possible sets of intramolecular force fields fitting fundamental vibrational frequencies and centrifugal distortion constants in the case ofXY ₃ pyramidal type molecules. The method is applied to PF₃ molecule as an example. It is found that there exist as many as four sets of force field fitting all the above experimental data. A few general criteria are suggested to eliminate the suprious sets, thus making further experimental data unnecessary to fix the true physical force field.     

离心力场作用下三维流动和传热的场协同理论探讨

通过对能量方程进行体积分得到了三维流场中场协同理论的表达式。该式不仅含速度矢量与温度梯度矢量的点积项,还含有速度矢量与压力梯度矢量的点积项。在此基础上讨论了速度场、压力场、温度场之间的协同关系,探讨了通过政变边界条件调节诸场形态,实现传热强化的方法。并通过三个盘腔算例,对此方法进行了验证。     

Application of DPIV to study both steady state and transient turbomachinery flows

Digital particle imaging velocimetry (DPIV) is a powerful measurement technique, which can be used as an alternative or complementary approach to laser doppler velocimetry (LDV) in a wide range of research applications. The instantaneous planar velocity measurements obtained with PIV make it an attractive technique for use in the study of the complex flow fields encountered in turbomachinery. The planar nature of the technique also significantly reduces the facility run time over point-based techniques. Techniques for optical access, light sheet delivery, CCD camera technology and particulate seeding are discussed. Results from the successful application of the PIV technique to both the blade passage region of a transonic axial compressor and the diffuser region of a high speed centrifugal compressor are presented. Both instantaneous and time-averaged flow fields were obtained. The averaged flow field measurements are used to estimate the flow turbulence intensity. The instantaneous velocity vector maps obtained during compressor surge provide previously unobtainable insight into the complex flow field characteristics occurring during short lived surge events. These flow field maps illustrate the true power of the DPIV technique.     

Short-ranged potential effects on the recurrence spectra of lithium M = 1 atoms in parallel electric and magnetic fields

This paper presents recurrence spectra of highly excited lithium atoms with M = 1 state in parallel electric and magnetic fields at a fixed scaled energy ε = -0.03. Short-ranged potentials including ionic core potential and centrifugal barrier are taken into account. Their effects on the states and photo-absorption spectrum are analysed in detail. This demonstrates that the geometric features of classical orbits are of special importance for modulations of the spectral pattern. Thus the weak polarization as well as the reduction of correlation of electrons induced by short-ranged potentials give rise to the recurrence spectra of lithium M = 1 atoms more compact than that of the M = 0 one, which is in good agreement with the experimental prediction.     

Experimental Investigation of Jet Stabilization in Near-Axis Region of Plasma Reactor

The paper presents the results of experimental investigations of aerodynamics and heat transfer in a vortex plasma reactor with gas jet injection along its axis. The process of mixing under quasi-isothermal conditions (injection of slightly heated jet) and inhomogeneous conditions (injection of helium and argon) as well as with the injection along the axis of plasma jet is studied consistently. A detailed comparison of temperature fields and concentrations is presented for these conditions. The process of jet expansion is shown to be defined mainly by three factors — centrifugal mass forces, buoyancy forces and initial velocity shift in a jet at the chamber inlet. The end flows contribute considerably to the process of jet mass transfer with peripheral flow.     

一先进跨音速离心压气机叶轮内部粘性流动数值模拟

随着计算机和计算技术的发展，三元粘性数值计算被广泛地应用于叶轮机械内部流场分析，本文使用三元Ｎ－Ｓ方程对这一先进跨音速离心压气机叶轮内部流场进行数值模拟，一是对这一成功设计进行分析验证。二是使用数值方法进行内部流场细节的模拟掌握其内部粘性流动特点，为今后设计和改进高压比跨音速离心压气机提供经验。     

基于非线性谐波法的离心压气机确定应力场分析

本文采用非线性谐波法与定常计算方法,对离心压气机的内部流场进行了数值模拟,对比了时均流场与定常流场的差别,研究了离心压气机确定应力分布的特点。结果表明,采用非线性谐波方法所得到的压气机内部流场宏观结构与定常结果基本一致,但流场参数分布细节存在较明显差别,且这种差别与对应的确定应力场的分布特征吻合,验证了确定应力是引起时均流场与定常流场差别的原因。对确定应力的分布特征分析表明,离心压气机内确定应力在流向上呈现为从叶轮出口向上下游逐渐递减的趋势,在叶高方向上表现为从叶根到叶顶逐渐递增趋势;且在整体上,确定应力的空间不均匀特性在叶轮出口处最为强烈,表明离心压气机内部最强非定常效应同样位于叶轮出口。     

离心泵蜗壳内旋涡流动的数值研究

采用"冻结转子法"处理叶轮与蜗壳间动静耦合流动的参数传递和相互干扰问题,研究了蜗壳进口周向非均匀来流对其内旋涡的演化发展的影响。分析表明,叶轮与蜗壳的干扰所造成的蜗壳进口周向流动的不均匀性是非常强烈的,整个蜗壳内的流动是以旋涡形式向出口推进的,且随工况的不同表现不同的演化过程,从而导致蜗壳内较大的流动损失。同时也说明只有考虑蜗壳来流的非均匀性影响,才能准确地模拟其内的旋涡运动。     

带有动力涡轮的双轴原理型燃气轮机的研制

描述了一种小型双轴原理型燃气轮机的研制过程。采用离心压气机,向心涡轮,单管燃烧室组成燃气发生器,电机通过齿轮箱由动力涡轮带动。简要介绍了一些主要部件的设计方法,给出了滑油系统和燃油系统原理图。对在研制和实验过程中所遇到的主要问题及其解决方法进行了介绍。经过多次实验表明文中给出的小型双轴原理型燃气轮机能够发出10kW电力,它可用来作为坦克燃气轮机主动力的模拟装置和一些车辆的辅机电站使用。     

含砂水对离心泵叶轮磨损的实验研究

黄河、长江流域的河水中泥砂含量较高,严重影响了这些地区输水水泵的使用寿命．本文利用固液两相流水泵实验台和一般的清水离心泵,在不同流量、不同砂粒粒径、不同含砂浓度条件下进行了磨损实验,弄清了上述参数对水泵叶轮磨损部位和程度的影响,为今后进一步探讨叶轮磨损机理和叶型改进提供了有益的实验资料。