Heat transfer of a row of three butane/air flame jets impinging on a flat plate

Experiments were performed to investigate the heat transfer characteristics of a row of three premixed, laminar, butane/air flame jets impinging on a water-cooled flat plate. The between-jet interference was found to reduce the heat transfer rate in the jet-to-jet interacting zone due to the depressed combustion. The interference became stronger when the jet-to-jet spacing and/or the nozzle-to-plate distance were/was small. The positive pressure existed in the between-jet interacting zone caused the asymmetric flame and heat transfer distribution of the side jet. The meeting point of the spreading wall jets of the central and the side jets did not occur at the midpoint of the neighboring jets, but at a location shifted slightly outwards. The maximum local heat flux and the maximum area-averaged heat flux occurred at a moderate nozzle-to-plate distance of 5d with a moderate jet-to-jet spacing of 5d. The lowest area-averaged heat flux was produced when both the jet-to-jet spacing and the nozzle-to-plate distance were small. Comparing with a single jet under the same experimental conditions, the heat transfer rates in both the stagnation point and the maximum heat transfer point were shown to be enhanced in a row of three-jet-impingement system. The present study provided detailed information on the heat transfer characteristics of a row of three in-line impinging flame jets, which had rarely been reported in previous study.     

一体化工作站在大气污染监测系统的应用

介绍工业污染源大气污染物排放连续监测系统的系统结构和应用范围。重点讨论一体化工作站在此系统中实际应用和性能特点。     

以外供液氮替代膨胀机的深度冷冻循环

介绍空分制氮装置采用膨胀机循环与液氮循环的两种工艺流程及能量平衡 ,示出了两种循环的实例比较。指出外供液氮可以作为冷源替代膨胀机 ,且单耗低、操作更方便 ,设备维护量更小、氮气提取率更高     

济钢120t转炉二次烟气除尘设计

济钢120t转炉二次烟气除尘设备选用长袋低压脉冲除尘器,风机采用液力偶合器,并设计将加料系统除尘风量直接加入转炉二次烟气除尘系统。系统投产后,每炉钢节电1200kW,烟气排放浓度为47mg/m3,烟气温度在110℃以下。实践证明,该系统具有节能、捕集率高、排放浓度低、自动化程度高等特点。     

位置控制器与通用变频器APC系统

在每一周期的开始时的速度值V1预设定到传动装置上进行速度预控制，同时，反馈回来的实际值Sj与S1进行比较计算，得出当时偏差值△S，此偏差值△S乘以比例系数Ksp，得到Vk叠加在Vt上，得出传动装置应具有的速度控制信号V，然后V经速度／电压变换和D／A转换向传动系统的速度控制发出控制信号Uα控制执行机构的定位。调节Ksp的值使系统无超调无振荡。     

燃气红外线辐射器的节能与环保特性分析

论述了燃气红外线辐射器的基本原理 ,对其节能与环保特性的分析表明 :与大气式燃烧器相比 ,红外线辐射器的燃料节约率为 15 %～ 45 % ,CO2 排放量减少率为 15 %～ 48% ,CO排放量减少率为 96.2 %～ 97.7% ,NOx 减少率为 94.9%～ 96.9% ,具有显著的节能与环保效果     

Chemical compositions and optical properties of HfOxNy thin films at different substrate temperatures

High-k HfO_xN_y thin films have been grown by radio frequency (rf) reactive sputtering of metal Hf target in N₂/Ar/O₂ ambient at different substrate temperatures. The chemical compositions of the films have been investigated as a function of substrate temperature by X-ray photoelectron spectroscopy (XPS). XPS measurements showed that nitrogen concentration increases with an increase in substrate temperature. Room-temperature spectroscopic ellipsometry (SE) with photon energy 0.75–6.5 eV was used to investigate the optical properties of the films. SE results demonstrated that refractive index n increases with an increase in substrate temperature. Based on TL parameters which were obtained from the best fit results used in a simulation of the measured spectra, meanwhile, we conclude that the energy band gap (E_g) decreases with an increase in substrate temperature.     

应当规范排(进)气阀的生产

输、配水管网因排气不畅而引发气爆型水锤，从而导致爆管的事故时有发生，经补救后再次发生爆管事故的也并不鲜见。近年来，我国的长距离、大口径管道输水工程快速发展，管道输水的排（进）气设计和排（进）气阀的规范生产问题应当引起重视。文中列举了有压管道输水系统中气体产生的原因、赋存形态和危害，对规范排（进）气阀的生产提出了建议。     

An investigation of the unstable region for dense phase conveying in sliding bed flow

For fine powdered materials, capable of being conveyed in dense phase, a conveying region exists in which instability in flow and pipeline blockage can occur if the pressure gradient available is insufficient to maintain a minimum value of solids loading ratio. A reduction in material flow rate can also lead to pipeline blockage in this region. Conveying trials under-taken with cement are used to illustrate the nature of the problem.     

空调器用风冷冷凝器换热能力实验研究

实验测定了几种不同铜管、肋片组合的冷凝器在不同的风量和风机转速下的换热量，发现采用内螺纹铜管和迎风侧平片、背风侧冲缝片的冷凝器具有最优的换热性能。分析了多流路冷凝器中不同流路之间的制冷剂分配不均匀性和再热现象。