工作压力对湿空气透平循环饱和器性能的影响

饱和器是湿空气透平（HAT）循环的主要部件之一,它的主要作用是加热加湿空气,从而提高整个HAT循环的效率和比功。利用IAPWS-IF97提供的水和水蒸气性质与实际气体状态方程,建立了适用高压条件下饱和器的一维传热传质数学模型;利用该模型计算了不同压力条件下的饱和器工作性能,并分析了饱和器内的传热传质过程中,饱和点的位置、出口性能参数的变化规律,以及能效值的变化,可以供饱和器的设计参考。     

水膜热阻修正系数对填料饱和器性能的影响

以单膜理论为基础,研究了饱和器内水与空气之间传热传质的过程,引入水膜热阻修正系数K的概念,建立了饱和器传热传质一维计算模型.通过数值模拟计算,分析了K对饱和器性能的影响,并确定了K设计值的取值范围.结果表明:饱和器出口水温、出口气温和出口空气含湿量受K设计值影响明显,K设计值越大,出口气温和出口空气含湿量越高,出口水温则越低;K设计值取得太小,水温和水膜温度相差较大,计算出的空气出口参数会偏小,反之,水膜温度几乎等于水温,计算出的空气出口参数会偏大,K设计值取15～100中的某一个值较为合理.     

Lewis因子及其对饱和器数值模拟的影响

讨论了Lewis因子和Lewis数两个不同概念的区别和联系,Lewis因子,也叫Lewis关系,表示蒸发过程中传热和传质的对比关系;建立了饱和器的一维数学模型,通过数值计算分析了Lewis因子对饱和器数值模拟结果的影响.     

内可逆往复式Maisotsenko-Brayton循环生态学性能优化

应用有限时间热力学理论,基于仅考虑传热损失的内可逆往复式Maisotsenko-Brayton循环模型,推导出了循环熵产率和生态学函数等重要参数表达式。通过数值计算,分析与研究了空气饱和器出口温度、循环最高温度和注水流率对循环性能的影响。将内可逆往复式Maisotsenko-Brayton循环与传统往复式Brayton循环进行比较,结果表明内可逆往复式Maisotsenko-Brayton循环性能优于传统往复式Brayton循环性能。     

模型饱和器冷态喷雾场的实验研究

针对HAT循环关键部件增湿饱和器内典型的传热，传质过程现象，为了最优化该过程和为今后数值分析提供有效的数据，设计了模拟饱和顺内传热，传质过程中的开放式冷态实验系统。使用相位多普勒分析仪DualPDA（Phase Doppler Analyzer）对冷态模型饱和器的喷雾场进行了详细的实验研究，测量了不同水压，不同气流速度下的喷雾场，得到喷雾场内液滴的三维平均速度分布，脉动速度分布，平均粒径大小分布等，分析了喷雾水压和鼓风气流速度对喷雾场的影响，分析结果表明，改良设计的离心喷嘴具用良好的喷雾性能和轴对称性，水压增大可以增大喷雾场中粒子速度，通量及降低平均直径，喷嘴喷雾长度随气流速度减小，气流速度可以改变喷雾场的分布，有利于液滴蒸发和液滴破裂。     

包含多变过程的内可逆Otto循环有限时间热力学分析

应用有限时间热力学理论分析了包含多变过程的内可逆Otto循环,由数值计算给出了考虑传热损失时循环输出功与压缩比、效率与压缩比以及输出功与效率的特性关系,分析了多变指数和传热损失对循环性能的影响,通过分析可知多变指数和传热对Otto循环性能有较大影响。计算所得的结果对实际Otto热机的设计和改进有一定的指导意义。     

HAT循环饱和器性能的(火用)分析

饱各器是HAT循环中的关键部件,对其性能的认识关系到整个系统的性能分析。由于饱和器内存在复杂的气液两相流动和相互间的传热质过程,其性能与很多参数有关,因此用一个或多个指标从一个或多个方面来评价饱和器性能问题一直是在研究的问题。本文使用了分析的方法,建立了饱和器衡模型,分析了内部损失,提出了性能评价的方法和4个评价指标:热力学完善度、效率、损系数和流密度变化率,通过这些评定准则可以对饱和器用能水平作出评价,为今后饱和器的设计和性能分析提供了参考。     

HAT循环饱和器性能的炯分析

饱各器是HAT循环中的关键部件，对其性能的认识关系到整个系统的性能分析。由于饱和器内存在复杂的气液两相流动和相互间的传热质过程，其性能与很多参数有关，因此用一个或多个指标从一个或多个方面来评价饱和器性能问题一直是在研究的问题。本文使用了炯分析的方法，建立了饱和器炯衡模型，分析了内部炯损失，提出了性能评价的方法和4个评价指标：热力学完善度、炯效率、炯损系数和炯流密度变化率，通过这些评定准则可以对饱和器用能水平作出评价，为今后饱和器的设计和性能分析提供了参考。     

逆流喷雾式饱和器内两相速度场的实验研究

应用三维粒子动态分析仪(PDA)和二维粒子速度分析仪(PIV)对逆流喷雾式饱和器内湿化过程的气液两相流流场进行了实验测量。通过稳态和瞬态速度场的测量结果,获得了饱和器内各点上水滴的三维平均速度、平均粒径和平均体积流量,以及饱和器中心线上的测量区域内水滴的瞬态速度分布和流线,给出了逆流喷雾式饱和器内液相水滴的三维平均速度、平均粒径和平均体积流量的分布规律,揭示了其内部流动的高紊流特性。图4表1参7     

气液降膜流动传热传质研究的综述

气液降膜是工业中常见的传热传质过程,在很多领域中有着广泛的应用,在湿空气透平（HAT）循环的主要部件饱和器中,也有着重要的意义。本文回顾了降膜分别在气体剪切力下以及由界面相变引起的热非平衡状态下的流动稳定性及传热传质的发展现状和研究进展,总结了气液降膜流动已有的理论和实验结果,并展望了气液降膜流动技术的发展前景。     

Numerical simulation of counter-flow spray saturator for humid air turbine cycle

The numerical simulations of simultaneous heat and mass transfer process in the counter-flow spray saturator and humid air turbine cycle are carried out in this work, according to the experimental conditions and actual size of a prototype saturator. This humidifying process involves two-phase flow of air and water droplets, also including interaction, breakup and collision of water droplets. Eulerian approach is used for gas phase flow, Lagrangian approach is used for liquid phase flow, and the two-way coupling is used between two phases. The simulations agree well with the experimental measurements. The simulations show the flow is with high turbulence intensity, the relative humidity and temperature of humid air increase along with the height of saturator, some water droplets carried by air escape from the saturator, and the humid air is mainly humidified at the lower part of saturator and is simultaneously humidified and heated at the upper part.     

逆流喷雾式饱和器内湿化过程的实验研究

对逆流喷雾式饱和器内部空气的湿化过程进行实验研究,实验中不仅测量了饱和器进出口湿空气的相对湿度、温度和水的温度,而且也测量了饱和器内部几个高度截面上湿空气的相对湿度和气相、液相的温度。根据实验测量的湿空气的相对湿度和温度,计算出了饱和器内湿空气的含湿量和测量高度间湿空气的加湿量。由实验结果可见,随水气质量比的增大,饱和器出口湿空气的温度和温升也相应增大。湿空气的含湿量和水的蒸发量、出口温度随进口水温升高、水气质量比增大而增大。在所有实验工况下,饱和器出口湿空气接近或达到饱和。随空气速度增大水滴逃逸量增大。总体上饱和器内部下部主要是加湿进口空气,上部是加湿和加热空气。     

喷水塔饱和器的动态建模与仿真

讨论了建立喷水塔饱和器的一维动态模型的方法。该方法将饱和器沿高度方向分解为若干段,每个段用气体和水滴模块表示。通过建立显式仿真模型,可以得到饱和器在稳定状态下和动态过程中参数的变化规律。根据模型稳定状态的数据。沿气体的主要流动方向,压力变化基本呈线性关系,而其它参数的变化为非线性。模型动态仿真结果表明,饱和器中气体压力和水之间的相互作用属于快过程,表现出与换热器不同的特点。     

Saturator analysis for an evaporative gas turbine cycle

In this paper a thermodynamic assessment and a preliminary cost evaluation are given for an evaporative gas turbine (EvGT) cycle packed humidifier. Both background theory and simulation results are included.Two different approaches were used for the humidifier system modelling: the full integration of the mass-energy balance and mass transfer equations (called SAT model), and an atmospheric cooling tower-based model (called CT model). Both approaches were used to perform component thermodynamic analyses and to determine the humidifier packing design.Within these approaches, two simulation cases are discussed: a test case, with experimental results from the pilot-plant of the University of Lund, and a case study of the saturators for the optimised HAT (humid air turbine) cycles of a plant with a 50 MW power output. The two cases presented consider two different operating conditions for the saturator: the first being a “non-optimised” saturator, and the later the “optimal” configuration with reduced exergetic losses. For the case study, the saturator design and cost evaluation are also included.All simulation results were performed with the in-house SAT (SATurator simulation tool) code.     

Experimental investigation of pressurized packing saturator for humid air turbine cycle

Humid air turbine (HAT) cycle is an advanced power generation system, and its efficiency and output power are improved by humidifying the compressed air. This humidification process is completed in the saturator. Therefore, the humidifying performance of saturator has great influence on the performance of HAT cycle. In this work, a new type packing saturator was designed and a series of experiments were carried out to study its humidifying performance. In order to improve the uniformity of the saturator inlet, a twin-tangential annular flow gas distributor was designed. Then it was authorized by China invention patents (ZL201010200778.9). Now, the mal-distribution factor of inlet air is mainly between 0.15 and 0.35 in all experimental conditions. Some key parameters of air and water at the inlet and outlet of saturator were measured at different experimental conditions. These results show the outlet humid air temperature is an important parameter for determining the humidifying amount of the saturator. The humidifying performance of the saturator is mainly affected by the inlet water temperature and the liquid/gas (L/G) ratio. At the same operating pressure, the humidity ratio of outlet humid air increases with inlet water temperature and L/G ratio. At higher inlet water temperature, the L/G ratio has a greater effect on the humidity ratio of outlet humid air. The outlet water temperature is mainly affected by the inlet gas temperature. With the increasing of inlet air temperature, the outlet water temperature increases, and it is close to the wet-bulb temperature of inlet air.     

Effect of regeneration mode on the performance of liquid desiccant packed bed regenerator

The regenerator is one of the key components in liquid desiccant air-conditioning systems, in which desiccant is concentrated and can be reused in the system. The regeneration heat is supplied into the regenerator by either hot air or hot desiccant. The heat and mass transfer performances of these two regeneration modes are analyzed and compared in detail. In the hot air driven regenerator, the parallel-flow regenerator has the best mass transfer performance and the counter-flow performs poorest under the same conditions, because the heat transfer process is the governing process and the mass transfer performance depends on the promotion of the heat transfer to the mass transfer process. In the hot desiccant driven regenerator, counter-flow configuration has the best mass transfer performance and parallel-flow is the poorest at the same conditions, since mass transfer is the governing process. Regeneration heat should be chosen to heat the desiccant instead of the air in the packed bed regenerator, since the hot desiccant driven regenerator has apparent better mass transfer performance. The proposed regeneration mode and flow pattern will be helpful in the design and optimization of the regenerators.