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101.
102.
分析了鱼雷热动力系统流体动力噪声产生的原因和排气噪声的基本机理,提出了齿轮泵、柱塞泵、控制阀及管道的流体动力噪声的控制措施,其中控制压力和流量脉动是流体动力噪声控制的主要内容。通过对排气噪声的频谱分析及对排气噪声控制方法的讨论,认为消声器能有效控制排气噪声。 相似文献
103.
纸浆消泡剂的合成及性能试验 总被引:1,自引:0,他引:1
研制了一种高效无毒纸浆消泡剂,其基本结构是聚醚的高级脂肪酸酯。并对酯化方法(包括催化剂的选择)和聚醚的分子量等进行了研究。 相似文献
104.
齿轮泵的流量脉动机理分析与设计 总被引:1,自引:0,他引:1
齿轮泵流基脉动大的缺点限制了其应用的范围,因此对于齿轮泵流量脉动的研究尤为重要。文中研究了齿轮泵流量脉动的机理,探讨了瞬时流量脉动规律,指出齿轮泵流量脉动的本质,并用错齿方法设计出流量为25L/min的错齿泵。 相似文献
105.
由于制浆造纸废水的难生物降解性,水解酸化被广泛地应用于制浆造纸行业的废水处理中。针对制浆造纸不同原料不同工艺所产生废水的特点,通过实验及实际运行收集数据的分析,总结出一些水解酸化工艺应用于制浆造纸废水处理中的一些设计及运行管理参数和经验之谈。 相似文献
106.
Pulp fibre suspensions display non-Newtonian rheology, including a yield stress. In mixing operations, this creates regions of active motion around the impellers with the cavern size affecting the quality of mixing attained. Due to the opacity of the suspensions, two non-invasive techniques were evaluated for determining cavern dimensions: electrical resistance tomography (ERT) and ultrasonic Doppler velocimetry (UDV), with ERT chosen for most tests due to the speed of data acquisition. Cavern volume as a function of impeller speed is reported for a range of mixing conditions (hardwood and softwood pulp, suspension mass concentrations from one to five percent, two impeller offsets from the wall, and three suspension height-to-chest diameter ratios). A scaled version of a commercial axial flow impeller was used in a standard side-entering configuration. Measured cavern diameters were compared against model predictions available in the literature. The discrepancy between experimental data and model predictions were significant and were attributed to interaction between the developing cavern and the vessel walls. An alternative model was developed for predicting cavern volume taking this interaction into account. 相似文献
107.
Zhengbiao Peng Zhulin Yuan Jie Cai Li Tie Chen Pan 《Chemical engineering science》2009,64(6):1249-1259
Drop formation in liquid-liquid fluidized bed was investigated experimentally. The normal water was injected via a fine-capillary spray nozzle into the co-flowing No. 25 transformer oil with jet directed upwards in a vertical fluidized bed. Experiments under a wide variety of conditions were conducted to investigate the instability dynamics of the jet, the size and size distribution of the drops. Details of drop formation, drop flow patterns and jet evolution were monitored in real-time by an ultra-high-speed digital CCD (charge couple device) camera. The Rosin-Rammler model was applied to characterize experimental drop size distributions. Final results demonstrate that drop formation in liquid-liquid system takes place on three absolutely different developing regimes: bubbling, laminar jetting and turbulent jetting, depending on the relative Reynolds number between the two phases. For different flow domains, dynamics of drop formation change significantly, involving mechanism of jet breakup, jet length pulsation, mean size and uniformity of the drops. The jet length fluctuates with time in variable and random amplitudes for a specified set of operated parameters. Good agreement is shown between the drop size and the Rosin-Rammler distribution function with the minimum correlation coefficient 0.9199. The mean drop diameter decreases all along with increasing jet flow rate. Especially after the relative Reynolds number exceeds a certain value about 3.5×104, the jet disrupts intensely into multiple small drops with a diameter mainly ranging from 1.0 to and a more and more uniform size distribution. The turbulent jetting regime of drop formation is the most preferable to the dynamic ice slurry making system. 相似文献
108.
Sara González-García Staffan Berg Ma Teresa Moreira 《The Science of the total environment》2009,407(11):3530-3539
Wood transportation from forest landing to forest-based industries uses large amounts of energy. In the case of Sweden, where forest operations are highly and efficiently mechanized, this stage consumes more fossil fuels than other elements of the wood supply chain (such as silviculture and logging operations). This paper intends to compare the environmental burdens associated to different wood transport models considering a Swedish pulp mill as a case study by using Life Cycle Assessment (LCA) as an analytical tool.Five scenarios (the current one and four alternative reliable scenarios) were proposed and analysed taking into account two variables. On the one hand, the influence of imported pulpwood share from Baltic countries and on the other hand, the use of rail transportation for wood transport. In particular, the following impact categories were assessed: Eutrophication, Global Warming, Photochemical Oxidant Formation, Acidification and Fossil fuel extraction. The environmental results indicate that transport alternatives including electric and diesel trains, as well as the reduction in Baltic wood imports should present better environmental performance than the current scenario in terms of all the impact categories under study. Remarkable differences were identified with regard to energy requirements. This divergence is related to different long-distance transport strategies (lorry, boat and/or train) as well as the relative import of wood selected.The combination of lorry and train in wood transportation from Southern Sweden plus the reduction of wood imports from 25% to 15% seems to be more favourable from an environmental perspective. The results obtained allow forecasting the importance of the wood transport strategy in the wood supply chain in LCA of forest products and the influence of energy requirements in the results. 相似文献
109.
CNG加气站压缩机的选择 总被引:3,自引:3,他引:0
论述了我国CNG加气站天然气压缩机的总体技术水平状况,压缩机选择的评估标准与技术要点。 相似文献
110.