逆向复式射流预燃室燃烧器煤粉颗粒行为预报

1引言预燃室燃烧技术是近十多年来开发研究的一种高燃烧效率低NO。的燃烧技术门．它是一种分级燃烧技术。燃料在预燃室内只是部分地燃烧,在贫氧的一次火焰区内脱挥发分,从而减少了NO。的形成。自1982年以来,我国开发研究了很多种类的预燃室,如旋流、大速差l‘］、偏置射流预燃室等。工程热物理研究所研究开发了逆向复式射流预燃室燃烧器l‘,‘］。经实验室和工业实验证明,该预燃室有极优良的火焰稳定性能和煤种适应性,能够实现较低的NOx排放。本文针对逆向射流预燃室内这一独特的流场结构,利用数值模拟来预报煤粉颗粒在其内的运…     

Limits on neutrino electromagnetic properties — an update

Limits on neutrino electromagnetic properties from laboratory experiments and astrophysical arguments are reviewed with an emphasis on the currently favored range of small neutrino masses. We derive a helioseismological limit on the charge and dipole moment for all flavors of e_ν6×10⁻¹⁴e and μ_ν4×10⁻¹⁰μ_B (Bohr magneton). The most restrictive limits remain those from the plasmon decay in globular-cluster stars of e_ν2×10⁻¹⁴e and μ_ν3×10⁻¹²μ_B.     

Boundary Effects on Exact Solutions of the Lagrangian-Averaged Navier–Stokes-α Equations

In order to clarify the behavior of solutions of the Lagrangian-averaged Navier–Stokes- (LANS-) equations in the presence of solid walls, we identify a variety of exact solutions of the full equations and their boundary layer approximations. The solutions demonstrate that boundary conditions suggested for the LANS- equations in the literature⁽¹⁾ for a bounded domain do not apply in a semi-infinite domain. The convergence to solutions of the Navier–Stokes equations as 0 is elucidated for infinite-energy solutions in a semi-infinite domain, and non-uniqueness of these solutions is discussed. We also study the boundary layer approximation of LANS- equations, denoted the Prandtl- equations, and report solutions for turbulent jets and wakes. Our version of the Prandtl- equations includes an extra term necessary to conserve linear momentum and corrects an earlier result of Cheskidov.⁽²⁾     

Remarks on Algebraic Lagrangian Formalism

An axiomatic approach to the notion of adjoint operator is provided within the framework of the algebraic Lagrangian formalism.     

Calculus over Commutative Algebras: A Concise User Guide

A short introduction to the theory of linear differential operators over commutative algebras is exposed.     

The simulation of electrified liquid jets

The simulation of a two-dimensional electrified liquid jet is described. A finite difference technique is coupled with a computational fluid dynamic code to solve Poisson's equation and the Navier-Stokes equations at the electrostatic fluid-flow interface. The dynamics of free-surface electrohydrodynamic fluid flow are simulated for a dielectric fluid in an electrostatics nozzle and a conducting two-dimensional jet. The fluid flow in a nozzle is compared with and without an applied electric field, and the effects of adding a grounded conducting cylinder to the configuration is demonstrated. A set of time sequence graphs are used to illustrate the breakup of a charged jet into droplets, and the influence of viscosity on jet formation and breakup is depicted.     

The temperature profiles in an argon plasma issuing into an argon atmosphere: A comparison of measurements and predictions

Experimental measurements and computed results are reported on a nontransferred argon plasma discharging into an argon environment in a laminar regime. The experimental data provide information on the temperature profiles, particularly those close to the torch exit. The mathematical representation of the system involves the simultaneous statement of the equations of continuity, motion, and thermal energy balance for an axisymmetric system, but for fully temperature-dependent property values. On the whole, the theoretical predictions are in very good agreement with the measurements, with the maximum discrepancy being of the order of 5–10%. This augurs well for the extension of this work to more complex systems, also including gas mixtures.     

Hopf bifurcation in annular liquid jets with mass transfer

A numerical study of Hopf bifuractions in annular liquid jets with mass transfer is presented. The study is based on the asymptotic equations which govern the dynamics of inviscid, incompressible, thin, annular liquid jets and on equilibrium conditions for mass transfer at the jet's inner and outer interfaces. It is shown that the amplitude of the time-periodic motion that results from the Hopf bifurcation increases whereas its frequency decreases as the solubility ratio is increased.