共查询到20条相似文献,搜索用时 62 毫秒
1.
GPB板式干燥机传热的计算与分析国内贸易部武汉科研设计院(430070)薛珠国1技术说明本干燥机为平板接触式干燥机,是鱼粉、啤酒糟、酒精糟、白酒糟、饲料载体干燥最理想的设备。由于物料与平板直接接触,是干燥机中热效率最高的一种结构形式,也是酒糟干燥处理... 相似文献
2.
根据国内蒸汽式粮食干燥机的使用现状 ,从理论和实践的结合上重点阐述了该机目前所存在的问题及其解决办法和途径 ,并且对改造后的经济效益作了较为客观的对比和分析 ,可作为有关方面的参考和借鉴 相似文献
3.
板式与管壳式换热器的比较分析 总被引:1,自引:0,他引:1
分析了管壳式换热器和板式换热器的结构、工艺性能、并通过比较认为板式换热器的换热工艺性能明显优于管壳式换热器,在油厂有较广阔的应用前景。 相似文献
4.
5.
板式换热器选型应用经验谈 总被引:1,自引:0,他引:1
板式换热器选型应用经验谈湖南湘澧盐矿魏敏关键词:板式换热器,应用1991年底,云南一平浪盐矿首次将板式换热器成功地应用于冷冻提硝的预冷系统,但由于实际流量小于设计流量,热负荷低于给定值,故传热系数未达到设计要求。我们在对一平浪盐矿实地考察的基础上,结... 相似文献
6.
7.
由于传统粮食干燥机的控制系统对粮食湿度的控制效果不佳,导致粮食干燥质量不高,故而本研究基于PLC的粮食干燥机控制系统优化设计.在系统硬件设计上,基于PLC设计电路,完善控制器.在系统的软件设计上,构建粮食温度采集模块,获取温度传感器输出信号,控制干燥机出口粮食湿度,调节蒸汽量,优化干燥机排粮速度,使各单元排粮速度相同.... 相似文献
8.
9.
10.
描述了一种小型内循环粮食干燥机的结构、原理和干燥作业过程,说明了其干燥特点,给出了这种小型干燥机的主要结构和性能参数。 相似文献
11.
分析比较了热交换器设计中常用的对数平均温差法和传热单元数法之间的联系和区别,并以增压柴油机的板翅式中冷器的设计为例,比较并验证了两种方法的设计结果.结果表明:两种方法设计出的换热器虽有一定偏差,但都可满足设计要求. 相似文献
12.
13.
Cleaning of milk fouling on plate heat exchanger surface causes intermittent downtime to milk processing industry. Fouling occurrence during milk pasteurization potentially reduces the heat transfer rate of plate heat exchanger (PHE), leading to serious energy deficiency. In this study, the development of milk surface foulant was successfully inhibited by superhydrophobic nanoparticulate coating of PHE surfaces. Full dispersion of multiwalled carbon nanotubes (MWCNTs) in hydrophobic polytetrafluoroethylene (PTFE) matrix was completed using ultrasonication and high temperature annealing techniques. Nanomorphology and surface structure of PTFE and CNT-PTFE films on stainless steel surface were interpreted by field emission scanning electron microscope (FESEM). To validate the hydrophobicity of the developed CNT-PTFE nanocomposite coated surface, a water contact angle (WCA) using a simplified sessile drop method, correspondent surface energy, foulant mass, and energy efficiency after milk pasteurization were estimated and compared with stainless steel 316 and polytetrafluoroethylene (PTFE) coated surfaces. Static contact angles for the control, PTFE-coated and CNT-PTFE surfaces increased from 71.2 to 119.6 and 141.1°, respectively. By application of CNT-PTFE nanocomposite coating, the estimated surface energy of heat exchanger surface decreased by 97.0% of its original value. After continuous milk pasteurization for 5 h, the mass of foulant on CNT-PTFE coated heat exchanger surface was 70.3% less than that of the uncoated surface; thus, total energy consumption of test PHE unit also dropped down by 10.2%. Developed CNT-PTFE nanocomposite coated surface will potentially reduce the risk of under-processed milk and decrease the frequency of the routine cleaning-in-place (CIP) program. 相似文献
14.
换热器管内强化传热的模拟分析 总被引:2,自引:0,他引:2
用CFD软件模拟流动场和温度场分布,得出纵流管壳式换热器不同结构形式的流动与传热的细观信息光滑管内,速度矢量与温度梯度矢量之间的夹角接近90°,传热效果较差;在管内插入物情况下,二者之间的夹角小于90°,流动场与温度场协同性更好,因而实现了强化传热. 相似文献
15.
为降低热管换热器的流动阻力并增强其换热效率,提出一种水滴形非均布热管换热器结构。使用计算流体力学软件ANSYS Fluent对传统错排热管阵列、水滴形热管阵列及非均布水滴形热管阵列的换热性能展开数值模拟,得到了其在不同雷诺数下的努塞尔数、阻力系数以及综合换热性能指标的变化曲线。对比分析结果表明:相对于传统错排热管阵列,水滴形热管阵列有效传热面积较大,内部流体流动无涡出现,流动摩擦较小,具有更大的努塞尔数以及更小的阻力系数,综合换热性能指标更佳;通过非均布设计,水滴形热管阵列内的流动紊流度增加,努塞尔数变大,换热性能增加。 相似文献
16.
In designing a network of heat exchangers for the recovery of waste heat, there is usually a'pinch' at which the minimum approach temperature difference limits energy recovery. Pinch technology emphasizes the importance of utility targets, which are independent of the network design, and so allow a very useful comparison with the utility requirements of actual networks. The design of a heat recovery network of exchangers used in palm oil refining has been examined using such pinch technology targeting procedures. The network was found to be well designed for the situation where steam is a cheaper utility than hot oil. As this was not the case, improved networks were designed. These allowed a significant reduction in heat exchanger surface area for the same energy consumption, or a 25% reduction in energy consumption for a modest increase in network area of about 10%. 相似文献
17.
18.
文章阐述了刮板式换热器的结构、原理,对刮板式换热器的工艺应用、内部流动规律、剪切速率、传热机制、停留时间分布和功率消耗等进行了系统性归纳,并对刮板式换热器未来的发展趋势和研究方向进行了展望。 相似文献
19.
为提高蒸汽换热器换热效率,提出了一种在水平换热管中插入芯棒的含芯棒蒸汽换热管结构,并通过采用Fluent中两相流模型分析了该结构中芯棒直径对换热管管内冷凝换热特性的影响规律。研究结果表明,由于芯棒的插入使得管内两相流流体的平均流速与管道壁面附近速度梯度增大,故换热管的换热效率得到有效提升;定量而言,换热管的换热效率在棒径比值处于0.52~0.57区间范围内时,换热管内蒸汽冷凝率最高及通流截面内速度梯度最大,此时换热效率达到最高,可确保较低的换热管出口温度和稳定的换热效率。此外,场协同性能分析结果还表明,协同角与棒径比值?呈正相关性,且当棒径比值?>0.52后,芯棒对水平换热管的强化传热效果明显。 相似文献
20.
通过数值对比研究了不同管排数对球突翅片管式换热器的换热和流动特性的影响.结果表明:随着管排数的增加,热量/压降(Q/ΔP)和COP值逐渐减少,2排管的Q/ΔP和COP值最大.在Re=1 138~3 415范围内,2排管平均Nu数分别比3,4,5排管增大11.1%,21.7%,23.2%.流场图显示,不同管排数均因球突增强了扰动,而强化了换热,但4,5排管的温度场几乎无变化,说明管排数的增加并不能增强换热.综上2排管换热综合性能较好. 相似文献