热管蒸发器烟气侧换热性能数值分析

针对热管蒸发器内烟气侧的流动和传热问题,建立三维几何模型,采用数值模拟的方法研究了不同雷诺数下翅片螺距、翅片高度、管间距等因素对螺旋翅片管束传热和阻力特性的影响。结果表明:在研究范围内,随着翅片螺距的增大,螺旋翅片管的传热性能增强;随着翅片高度和管间距的增加,螺旋翅片管的传热性能减弱。随着翅片高度的增加,螺旋翅片管的阻力增大,随着翅片螺距和管间距的增大,螺旋翅片管的阻力性能减弱。研究发现,在所选用的翅片尺寸范围内,当螺距为10 mm、翅片高度为5 mm、管间距为55 mm时综合换热性能最佳。     

H型翅片管湿烟气对流冷凝传热的数值模拟研究

通过数值计算对湿工况下的H型和圆型翅片管换热器通道内充分发展段的对流冷凝传热特性进行模拟研究。计算采用压力与速度耦合的SIMPLER算法,湿烟气流速范围为1~5 m/s,水蒸气质量分数范围为5%~13%。讨论了不同入口速度、水蒸气质量分数对H型翅片管和圆型翅片管传热传质系数、传热量、冷凝水流量和翅片效率的影响,并进行定量比较分析。计算结果表明,H型翅片管的传热能力强于圆型翅片管,但冷凝生成量较圆型翅片管小,同时H型翅片管的总翅片效率和潜热翅片效率小于圆型翅片管。     

H型翅片管湿烟气对流冷凝传热的数值模拟研究

通过数值计算对湿工况下的H型和圆型翅片管换热器通道内充分发展段的对流冷凝传热特性进行模拟研究。计算采用压力与速度耦合的SIMPLER算法,湿烟气流速范围为1～5 m/s,水蒸气质量分数范围为5%～13%。讨论了不同入口速度、水蒸气质量分数对H型翅片管和圆型翅片管传热传质系数、传热量、冷凝水流量和翅片效率的影响,并进行定量比较分析。计算结果表明,H型翅片管的传热能力强于圆型翅片管,但冷凝生成量较圆型翅片管小,同时H型翅片管的总翅片效率和潜热翅片效率小于圆型翅片管。     

文摘

翅片管广泛应用于废热锅炉、直火式加热器和有关的传热设备中。在选择翅片管过程中,涉及到一些变化因素,包括翅片管尺寸、成本以及允许的压降范围。然而,在实际选用翅片管过程中,设计人员往往容易忽视的一个重要问题是翅片管的翅片形状和密度对传热表面积需求的影响。他们常常会以     

套片式翅片管的热套工艺

针对方形翅片管加工特点,确定了翅片翻边的相关工艺尺寸,提出了套片式翅片管的热套工艺方案。介绍了翅片热套工艺的主要工艺参数的确定方法及其工艺质量控制要点。     

平直开缝翅片和波纹翅片管换热器换热特性的数值模拟

采用FLUENT数值模拟方法,研究了平直翅片、平直开缝翅片、正弦波纹翅片和均匀倾角波纹翅片4种形式的翅片管换热器的空气侧流动和传热特性。分析出2种不同的波纹形式以及翅片开缝对翅片管换热器换热特性的影响。改变进口风速,在不同雷诺数的工况下,得到4种换热器的换热量Q、努塞尔数Nu、压降△P以及阻力因子f等与进口风速u和雷诺数Re的关系。结果表明进口风速增大,雷诺数增加,可显著提高换热器换热量,然而同样带来更多的阻力损失。翅片开缝对传热能力有明显的提升作用,波纹翅片在提高换热效率的同时阻力损失增加较小。     

空气冷却器及其强化传热翅片管型

对干式、湿式以及干湿联合式空气冷却器的换热特点、常用的翅片管结构、三维翅片等强化传热翅型以及空气冷却器翅片管的加工工艺、选材等方面进行了综述研究。采用套片式加工工艺的条缝型错置带状三维翅片和采用无屑加工方法成形的锯齿翅片,在较低空气流速下具有较高的传热因子和摩擦因子比,是提高空气冷却器空气侧换热的高效翅片管型,为石化行业空气冷却器翅片管的改造提供参考。     

熵产最小化在板翅式换热器优化设计中的应用

在板翅式换热器热力学优化中,探索了模拟退火算法的应用。在给定的传热量和给定的约束条件下,以换热器的熵产数为优化目标函数,以换热器的长度,翅片数,流道数,翅片长度,翅片厚度,翅片高度为优化变量。通过对遗传算法对比,表明模拟退火算法在换热器优化中同样具有有效性与准确性,而且模拟退火算法具有通用性,可用于不同结构和尺寸换热器...     

轻柴油汽提塔底T形翅片管重沸器工艺设计与应用

介绍了T形翅片管用于重沸器中强化沸腾传热的机理及其性能特点,建立了T形翅片管重沸器设计计算模型。与HTRI计算光管重沸器相比,T形翅片管管外沸腾传热系数提高了约5倍,总传热系数提高了80.4%,重沸器面积裕量由原-26.58%增加为31.2%,工业应用证明T形翅片管重沸器很好地满足了装置提负后的生产要求,为T形翅片管重沸器工业设计提供了理论依据。     

空调器用小管径翅片管蒸发器的优化设计方法

提出了空调器用小管径翅片管蒸发器的优化设计方法。优化设计方法主要包括翅片结构设计和制冷剂流路设计。设计方法中,采用基于CFD的方法设计小管径翅片结构,并采用基于图论的仿真方法设计制冷剂流路。为了验证设计结果的合理性,对采用小管径翅片管蒸发器的空调整机进行了实验测试。实验结果验证了优化设计方法的正确性,表明采用小管径翅片管蒸发器的空调具有良好的性能。     

Soot Particle Aerosol Mass Spectrometer: Development,Validation, and Initial Application

The Soot Particle Aerosol Mass Spectrometer (SP-AMS) was developed to measure the chemical and physical properties of particles containing refractory black carbon (rBC). The SP-AMS is an Aerodyne Aerosol Mass Spectrometer (AMS) equipped with an intracavity laser vaporizer (1064 nm) based on the Single Particle Soot Photometer (SP2) design, in addition to the resistively heated, tungsten vaporizer used in a standard AMS. The SP-AMS can be operated with the laser vaporizer alone, with both the laser and tungsten vaporizers, or with the tungsten vaporizer alone. When operating with only the laser vaporizer, the SP-AMS is selectively sensitive to laser-light absorbing particles, such as ambient rBC-containing particles as well as metal nanoparticles, and measures both the refractory and nonrefractory components. When operated with both vaporizers and modulating the laser on and off, the instrument measures the refractory components of absorbing particles and the nonrefractory particulate matter of all sampled particles. The SP-AMS design, mass spectral interpretation, calibration, and sensitivity are described. Instrument calibrations yield a sensitivity of greater than 140 carbon ions detected per picogram of rBC mass sampled, a 3σ detection limit of less than 0.1 μg·m^?3 for 60 s averaging, and a mass-specific ionization efficiency relative to particulate nitrate of 0.2 ± 0.1. Sensitivities were found to vary depending upon laser-particle beam overlap. The utility of the instrument to characterize ambient rBC aerosol is demonstrated.

Copyright 2012 American Association for Aerosol Research     

两步法甲醇制丙烯过程全流程模拟与优化

使用Aspen Plus软件平台,通过用户自定义模块方法,对简化的两步法甲醇制丙烯(MTP)工艺流程包括反应工段、压缩工段和分离精制工段进行了全流程稳态模拟.通过动力学集总模型建立了用户自定义反应模块,模拟了MTP三段绝热固定床反应器内反应物轴向温度分布和浓度分布.通过用户自定义模块与其他内置模块的衔接,嵌入了自定义动...     

An optimization method for enhancement of gas–liquid mass transfer in a bubble column reactor based on the entropy generation extremum principle

In this study, an optimization method is proposed to enhance the gas–liquid mass transfer in bubble column reactor based on the entropy generation extremum principle. The mass transfer–induced entropy generation can be maximized with the increase of mass transfer rate, based on which the velocity field can be optimized. The oxygen gas–liquid mass transfer is the major rate–limiting step of the toluene emissions biodegradation process in bubble column reactor, so the entropy generation due to oxy...     

干气密封螺旋槽几何参数优选交互影响

为解决干气密封（DGS）端面型槽优化中未考虑型槽几何参数之间对目标函数交互影响而导致几何参数优化结果不准确的问题,研究了不同速度条件下DGS螺旋槽中其他几何参数对某一几何参数优选值的交互影响。基于气体润滑理论,建立了螺旋槽DGS的几何模型和数学模型,数值求解获得端面膜压分布和稳态性能参数,定义了综合表征螺旋槽几何结构的特征参数。以气膜刚度最大为优选目标,获得了不同速度条件下DGS螺旋槽中某一几何参数优选值随其他几何参数的变化规律。结果表明：DGS螺旋槽各几何参数两两之间呈现出复杂的交互影响关系,不过总体符合趋向于降低槽内实际通流面积、槽长宽比和槽长深比3个综合参数变化幅值的原则;与单因素优化方法相比,在给定算例参数条件下所提出的考虑几何参数交互影响的优化方法所获得气膜刚度最优值提高11.4%。     

工作站在轮胎结构优化设计及力学分析中的应用

简要介绍了工作站在轮胎结构设计及力学分析中的应用，如建立轮胎几何模型、材料模型及有限元模型，并通过分析解算、处理有限元分析结果完成轮胎结构优化设计，为轮胎结构设计人员在轮胎结构优化设计、力学分析等工作中提供了一个强有力的方法和工具。     

深冷设备储罐罐壁温度场计算分析

深冷设备储罐内外壁温差较大,绝热结构复杂。当维持操作条件一定,控制储罐热流量不变时,减薄保冷层结构,选择合适的保冷材料,可以节约存储空间。根据传热理论运用传热控制方程,对某厂深冷设备储罐进行分析。建立了储罐罐壁的二维稳态温度场数值有限元计算模型,计算得到罐壁温度场分布图。根据公式,绘制出保冷层厚度与保冷材料导热系数之间的关系。研究结果对储罐的结构设计优化具有一定的指导意义。     

Optimum design of integrated liquid recovery plants by variable population size genetic algorithm

Increase in the price of energy sources as well as economic problems have caused cryogenic natural gas plants to become more complex and efficient. After selecting the process configuration, the flow rate, pressure, and temperature of the process fluid streams are determining factors which should be tuned in order to find the optimum condition. Products specification and operating costs of the plant are two significant parameters which should be considered in an optimal design. Moreover, process design limitations contribute to the problem being more difficult. This paper shows how the optimal operating point in an integrated NGL recovery plant can be found through solving a complex constrained optimization problem. A Variable Population size Genetic Algorithm (VPGA) was used for optimization. As well, the role of VPGA algorithm parameters in solving the process design problems is investigated in this study. The analysis showed that the VPGA method has better performance compared to the general GA methods. The plant‐wide net profit increases 12493360 $/year only by changing the selected operating conditions to its optimal value.     

循环水加热汽化器的设计分析

介绍一种利用循环热水加热低温液体的汽化器设计理念.阐述该设备的设计可行性,设计基本思路及理论计算模式,并探讨在实际运行中需要控制的运行参数和注意的问题.     

Power scheduling and real-time optimization of industrial cogeneration plants

Scheduling of power and real-time optimization for three industrial cogeneration plants at one of Dow's Louisiana site is presented in this paper. A first principle mathematical model that includes mass and energy balances for gas turbines, heat recovery units, steam turbines, pressure relief valves and steam headers is used to formulate an optimization problem to recommend the best strategy to trade power. The model has detailed operational information that includes equipment status and control curves for different operating scenarios. The model can also accurately predict the effect of ambient temperature, thereby resulting in an optimal day-ahead schedule. Adjustment of power schedule is done in the real-time market 30 min prior to the hour and implementation of the dispatched power schedule is done using a model predictive controller.