城市原生污水两相流特性研究

发布时间：2018-06-06 21:00

本文选题：城市原生污水 + 污水源热泵　；参考：《中国矿业大学》2014年硕士论文

【摘要】：目前，建筑空调、采暖能耗日益增大。大量的城市污水含有巨大的能量，被污水源热泵技术利用后能在很大程度上缓解建筑空调及采暖方面的能耗压力。但是目前，国内对污水源热泵的研究大部分都侧重于污水源热泵系统的价值与前景方面，缺乏基础理论的指导。城市污水的流动特性是污水源热泵系统水力与换热工况设计计算的重要问题，是系统稳定运行的关键，由于对城市污水流动特性的研究严重缺乏，因此在管路与换热设备的设计方面缺少理论依据。本文围绕城市原生污水两相流动特性，对城市原生污水在圆管以及热管换热器流道中的流动特性、临界流速以及颗粒的运动进行了分析，旨在为污水冷热源的应用与推广提供依据。由于城市原生污水水质的复杂性，污水源热泵技术面临很多挑战和困难。本文首先从污水流动特性方面着手，运用两相流理论并结合物理实验及Fluent数值模拟，对污水在圆管中的流动性进行分析。污水在层流状态时，流速较小，污水中大部分颗粒已经沉降管底，悬浮液为两相流均质流体，因此用非牛顿流体模型进行分析。在紊流状态时，流速较大，大量颗粒处于悬浮状态，用两相流模型进行分析。最终获得其层流和紊流状态下污水的速度分布和阻力损失的计算方法，对污水源热泵系统设计和水力计算提供借鉴和参考。本文对污水在一种热管换热器中的流动性进行了分析，该换热器流道侧壁为并列排置的热管，流体在每两并列排置的热管间流动。为了解该特殊流道下，污水的流动特性，本文通过模拟分析了热管换热器的热管尺寸、截面形状以及流速大小三个主要因素对污水在该特殊流道中流动特性的影响，并结合实验得到污水在该类热管换热器中的流动阻力系数计算式，为该类型热管换热器优化设计提供依据。污水源热泵系统中，管道和换热设备结垢和堵塞一直以来阻碍着污水源热泵的发展。本文从污垢的源头—固相颗粒角度出发，分析了固相颗粒在圆管不同流速时以及在热管换热器中的不同热管直径、不同流道形状、不同流速时的运动轨迹，为污水源热泵系统防垢方面提供依据。本文对城市原生污水两相流特性的研究与分析，，为污水源热泵系统的设计及管理提供借鉴和参考，为污水源热泵技术的进一步研究提供理论依据
[Abstract]:At present, building air conditioning, heating energy consumption is increasing. A large amount of urban sewage contains huge energy, which can alleviate the energy consumption pressure of building air conditioning and heating to a great extent after being used by sewage source heat pump technology. However, most of the domestic researches on sewage source heat pump are focused on the value and prospect of sewage source heat pump system, which lacks the guidance of basic theory. The flow characteristics of municipal sewage is an important problem in the design and calculation of the hydraulic and heat transfer conditions of sewage source heat pump system, which is the key to the stable operation of the system. Therefore, there is a lack of theoretical basis in the design of pipeline and heat exchanger. In this paper, the flow characteristics, critical velocity and particle movement of urban primary sewage in circular pipe and heat pipe heat exchanger are analyzed around the two-phase flow characteristics. The purpose of this paper is to provide the basis for the application and popularization of sewage cooling and heat sources. Due to the complexity of urban primary sewage water quality, sewage source heat pump technology is facing many challenges and difficulties. In this paper, the flowability of sewage in circular pipes is analyzed by using two-phase flow theory, physical experiments and fluent numerical simulation. In laminar flow, the flow velocity of sewage is small, most of the particles in the sewage have already settled at the bottom of the pipe, and the suspension is a two-phase flow homogeneous fluid, so the non-Newtonian fluid model is used to analyze it. In the turbulent state, the velocity is large and a large number of particles are suspended. The two-phase flow model is used to analyze it. Finally, the calculation method of velocity distribution and resistance loss of sewage under laminar and turbulent conditions is obtained. In this paper, the fluidity of sewage in a heat pipe heat exchanger is analyzed. The side wall of the channel of the heat exchanger is a heat pipe arranged in parallel. Fluid flows between two parallel heat pipes. In order to understand the flow characteristics of sewage in this special channel, the influence of three main factors, such as the size of heat pipe, the shape of cross section and the flow rate of heat pipe heat exchanger, on the flow characteristics of sewage in the special channel is analyzed by simulation in this paper. The calculation formula of flow resistance coefficient of sewage in the heat pipe heat exchanger is obtained, which provides the basis for the optimal design of the heat pipe heat exchanger. Fouling and blocking of pipes and heat exchangers have been hindering the development of sewage source heat pumps. In this paper, from the point of view of the source of fouling-solid particles, the motion trajectories of solid particles at different flow rates in circular tubes and in heat pipe heat exchangers with different heat pipe diameters, different flow channel shapes and different flow rates are analyzed. This paper studies and analyzes the characteristics of urban sewage two-phase flow, and provides reference for the design and management of sewage source heat pump system. Provide theoretical basis for further research of sewage source heat pump technology
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU83

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