【作者】 熊庭；

【导师】 范世东；

【作者基本信息】 武汉理工大学 ， 载运工具运用工程， 2011， 博士

【摘要】 绞吸式挖泥船进行疏浚作业在湖泊清淤、航道整治、港口建设和吹填造地等工程中广泛应用并发挥着重要作用。在绞吸式挖泥船施工过程中,疏浚泥浆通过长距离输泥管道从挖掘水域排放到泥浆存放点,由于疏浚泥浆具有浓度高、颗粒不均匀和成份复杂等特点,因此在长距离输送过程中存在管道阻力大、输送能耗高、管道堵塞和排泥距离受到限制等技术问题,严重地影响着疏浚挖泥船的生产效率、作业范围和生产成本。解决这些问题的关键点就是如何利用管道助推技术减小管道阻力,延长管道输送距离,同时还能减少管道磨损。论文中围绕加气输送的减阻机理、减阻效果、减阻范围等问题开展研究,主要研究内容分为理论、实验及应用三大部分。理论方面主要包括明确疏浚泥浆的基本性质和分类,分析泥浆在管道内部的流态,分析气体喷入泥浆后对管道内部流态的影响。判断不同输送参数下管道内部泥浆的流型,主要分为分层流、定床段塞流、动床段塞流及均匀段基流四种流型。根据不同流型分析其管道输送数学模型,将气体流量、泥浆流量、泥浆密度、泥浆体积浓度和管道直径等参数代入理论模型进行计算,得出管道内部的压力分布数据,利用压力梯度的大小评价管道阻力。将各工况下的管道阻力进行比较,找出管道输送的临界加气速度以及临界泥浆流速。试验方面首先是优化改造加气输送试验台,主要包括对数据采集系统及测控系统的优化以及对加气关键设备的设计。然后设计试验方案,主要通过调整主泵功率来调节泥浆流量,通过调整空压机加气压力来调节气体流量,泥浆体积浓度从清水到30%浓度逐步递增。试验采集了大量的数据并进行归纳整理,与理论模型的计算结果进行对比,检验加气输送数学模型的准确性并明确数学模型的适用范围。评价加气设备的功效和加气输送减阻效果,为管道加气输送技术提供理论基础和试验依据。应用研究主要是开展加气输送系统的适用性评价。首先将加气系统更换为工程中普遍应用的接力泵输送系统,进行不同泥浆浓度及流量下的试验,采集管路输送系统的各项数据,将接力泵输送系统和加气输送系统进行对比,主要分析两种输送系统在流量、排距、产量及能耗方面的优劣,明确各自的应用范围。更多还原

【Abstract】 Cutter suction dredger plays an important role in engineering projects with its wide application in lake dredging, channel regulation, port construction and land reclamation, and so on. To transport slurry in long distance from dredging waters to slurry storage place, the dredging projects often encounter limitation on efficience, operation scope and operation costs and meet probles like huge pipe resistance, high energy consuming, pipe blocking and short transportation distance, since slurry has the features like its high concentration, nonuniform particles and complex ingredients. The key of the solution to such limitation and problem lies in how to apply aided techniques to reduce pipe resistence and lengthen transportation distance with less abrasion.This dissertation researches on resistance reducing mechanism, its effect and relevant scope from the theoretical, experimental and applied levels. The theoretical research includes identifing the quality and category of slurry, analyzing slurry flow states in the inner pipe and how such states change after air injection to pipes. Here flow states under various parameters in the inner pipes are mainly divided into 4 types such as stratified flow, slug flow over a stationary bed, slug flow over a moving bed, and fully suspended slug flow as well. These four flow types have their respective mathematical modals to calculate inner pipe pressure distritution with relevant parameters of gas flow, slurry flow, slurry density, slurry concenration and pipe diameter. The pressure distritution reflects corresponding resistance force in pipe and helps to identify critical velocities of injected gas and transported slurry.Experimental research first focuses on optimizitation of gas-injected transportation test-bed, invovling optimized data-collecting system,monitoring system and air-injector.The next attention is given to testing plans, which adjust slurry flow through power change of main pump, reinforce gas flow through air compressor, and increase slurry concentration from clear water to 30%.The experimental research sorts out groups of data and makes comparison with the calculated results from theoretical models to examine accuracy and applicability of mathematical models, providing theoretical basis and evidence to air-injected effect and resistance reducing efficeincy.Applied research gives assessments to the applicability of the whole air-injected transportation system. The gas-injected equipments are exchanged for commonly-applied relay pump equipments, which are tested under different slurry concentration and flow. The two systematical data are comparatively analyzed from the aspects of flow, transportation distance, output of slurry, and energy consumption to identify their respective advantages and disadvantage to serve as reference to engineering projects.更多还原