论文总字数：18380字

摘 要

我国拥有960万平方公里的国土面积，人口众多，随着社会进步及人民生活水平的提高，果蔬的需求越来越大。国内外在各自领域都有不同的果蔬干燥手段，但是原来的技术存在生产成本高，果蔬干品质不高，不易存放。但最需要解决的问题是果蔬干燥膨化加热冷却时间长、膨化效率低、传热不均匀。干燥的目的具体有提高果品品相、脆度、色泽。干燥设备所需要的物料及传热工质也有很高要求，市面上采用热管作为传热材料已经成为一种趋势，因为热管的传热效率高，传输热量均匀。通过使用热管并在95℃的加热加压过程与在90℃的抽真空过程比用蒸汽管所需要的干燥时间大大降低。

关键词：果蔬 膨化干燥 热管

Development and design of 10kg fruit and vegetable drying and expanding heat pipe

Abstract

China has 9.6 million square kilometers of land area, population is numerous, along with social progress and people's living standards improve, fruit and vegetable demand more and more. At home and abroad in their respective fields have different fruits and vegetables drying means, but the original technology production costs high, dry fruits and vegetables quality is not high, is not easy to store. But the need to solve the problem is the fruit and vegetable drying and puffing heating and cooling for a long time, puffing efficiency is low, the heat transfer is not uniform. Dry specifically to improve fruit quality, crisp, color. Drying equipment needed materials and heat transfer fluids have very high requirements on the market using heat pipe as a heat transfer material has become a trend, because The heat transfer efficiency of the heat pipe is high, uniform heat transfer. By using the heat pipe and the heating and pressing process at 95 degrees C and the vacuum process at 90 C, the drying time required for the steam pipe is greatly reduced.

Key Words: fruit and vegetable;expansion drying;heat pipe

目录

摘要…………………………………………………………………………………..I

ABSTRACT ………………………………………………………………………II

第一章 绪论………………………………………………………………………..1

1.1课题背景……………………………………………………………………1

1.2现有干燥技术…………………………………………………………....…1

1.2.1热管分类………………………………………………………………2

1.2.2干燥技术……………………………………………………………….6

1.3国内外现状………………………………………………………………......7

1.4未来发展方向……………………………………………………………….7

1.4.1热泵干燥技术…………………………………………………….......8

1.4.2热管技术……………………………………………………………...8

1.5课题研究内容………………………………………………………………..8

1.6本章小结…………………………………………………………………......9

第二章 干燥工艺分析及计算………………………………………………......9

2.1 原工艺的问题和改进………………………………………….......……......9

2.1.1 原工艺存在的问题……………………………………………............9

2.2 果蔬加热干燥过程具体流程……………………………………….............9

2.3 干燥罐工艺参数…………………………………………………….............9

2.3.1加压干燥阶段干燥罐的温度、压力…………………………….........9

2.3.2 恒温真空抽干阶段干燥罐的温度、压力………………………........9

2.3.3 果干加工工艺参数及表面积……………………………………......10

2.3.4 干燥罐和热管的基本结构参数………………………………........10

2.4 果蔬干燥过程热力计算……………………………………………...........12

2.5热管与翅片设计………………………………………………………........12

2.5.1 热管内工作介质的选择…………………………………………......13

2.5.2 热管的外壳材料的选择及强度计算……………………………......14

2.5.3翅片工艺参数…………………………………………………….......14

2.6 翅片的选择和热管工艺参数………………………………………….......14

2.6.1 翅片选择…………………………………………………………......15

2.6.2 热管的工艺参数确定……………………………………………......16

2.7 热管壁面换热计算…………………………………………………….......16

2.7.1 加热加压过程……………………………………………………......17

2.7.2 膨化过程…………………………………………………………......17

2.8 加热加压过程分析…………………………………………………….......18

2.9 膨化过程的分析……………………………………………………….......19

2.10 保温真空抽干阶段…………………………………………………….....19

2.10.1已知条件………………………………………………………….....19

2.10.2热力分析………………………………………………………….....20

2.10.3膨化罐壁面换热系数…………………………………………….....20

2.10.4热管换热系数计算……………………………………………….....21

2.10.5保温真空抽干过程换热量计算………………………………….....21

2.10.6保温真空抽干阶段总换热量及换热时间计算………………….....22

2.11本章小结

第三章 结语 ……………………………………………………………………..23

参考文献…………………………………………………………………………...24

致谢…………………………………………………………………………………26

第一章 绪论

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