直接电加热滚塑工艺的传热分析

doi:10.19491/j.issn.1001-9278.2022.07.015

中国塑料 ›› 2022, Vol. 36 ›› Issue (7): 109-114.DOI: 10.19491/j.issn.1001-9278.2022.07.015

直接电加热滚塑工艺的传热分析

刘学军()

北京工商大学人工智能学院，北京 100048

收稿日期:2022-01-10 出版日期:2022-07-26 发布日期:2022-07-20
通讯作者: 刘学军（1968—），男，副教授，从事工程中流动与传热方面的研究，liuxj@th.btbu.edu.cn
E-mail:liuxj@th.btbu.edu.cn

Heat transfer analysis of rotational molding process heated directly with electricity

LIU Xuejun()

School of Artificial Intelligence，Beijing Technology and Business University，Beijing 100048，China

Received:2022-01-10 Online:2022-07-26 Published:2022-07-20
Contact: LIU Xuejun E-mail:liuxj@th.btbu.edu.cn

摘要/Abstract

摘要：

通过实验测量了直接电加热的滚塑模具在加热阶段的表面温度和模内温度以及所消耗的电能。然后根据实验数据对该滚塑工艺的加热阶段进行了传热分析，计算了有效热能和无效热能，并提出了评估该滚塑工艺的3个指标参数——热能利用率、加热每单位质量粉料所消耗的电能、加热每单位质量粉料所需的时间。结果表明，该滚塑模具的表面温度具有一定的不均匀性，不同位置处的最大温差为8 ℃。3种实验情形下的最高热能利用率为37.5 %，另外在相同的模内加热温度下，热能利用率随模内粉料质量的增大而减小。

关键词: 滚塑工艺, 直接电加热, 传热分析, 有效热能, 无效热能, 热能利用率

Abstract:

The temperatures at the surface of a rotational mold and inside the mold heated directly by electricity along with the consumed electric energy were measured in the heating stage. Based on the experimental data， a thermal analysis was conducted for the heating phase of the rotational molding process， and effective heat energy and ineffective heat energy were calculated. The rotational molding process was evaluated by three indexes， including the utilization rate of heat energy， the electricity consumed for heating powder per unit mass， and the time needed for heating powder per unit mass. The results indicated that the temperature distribution at the rotational mold surface is inhomogeneous， resulting in a maximum temperature difference of 8 ℃ at different locations. The highest utilization rate of heat energy was determined to be 37.5 % in three experimental cases. The utilization rate of heat energy decreased with an increase in the mass of powders inside the mold at the same heating temperature inside the mold.

Key words: rotational molding, direct electric heating, heat transfer analysis, effective heat energy, ineffective heat energy, utilization rate of heat energy

中图分类号:

TQ320.66

刘学军. 直接电加热滚塑工艺的传热分析[J]. 中国塑料, 2022, 36(7): 109-114.

LIU Xuejun. Heat transfer analysis of rotational molding process heated directly with electricity[J]. China Plastics, 2022, 36(7): 109-114.

图/表 10

图1 实验方案的示意图

Fig.1 Schematic of experimental plan

图2 直接电加热的滚塑模具

Fig.2 Rotational mold heated by electricity directly

图3 氢气瓶的剖面形状和尺寸

Fig.3 Cross section and dimension of hydrogen tank

名称	氢气瓶的厚度/mm	模内粉料的质量/kg	加热温度/℃
情形1	5	1.505	200
情形2	10	2.906	180
情形3	15	4.205	180

表1 3种实验情形

Tab.1 Three experimental cases

图4 在情形1下模具外表面温度的实测值

Fig.4 Tested temperature at the outer surface of the mold in case one

图5 模内温度的实测值

Fig.5 Tested temperature inside the mold

名称	加热时间/min	熔融时间/min	保温时间/min
情形1	16	8	4
情形2	25	17	3
情形3	56	34	13

表2 3种实验情形下的加热时间、熔融时间和保温时间

Tab.2 Heating time， melting time and holding time in three experimental cases

图6 在情形1下模具外表面的辐射热流随时间的变化规律

Fig.6 Variation of radiation heat flux at the outer surface of the mold with time in case one

E/kJ	Q_e/kJ	Q_r/kJ	Q_c/kJ	Q_r/E	Q_c/E
6 120	2 246	191	3 683	3.1 %	60.2 %

表3 情形1的E、Qe、Qr、Qc以及Qr/E和Qc/E

Tab.3 E， Qe， Qr， Qc and Qr/E and Qc/E in case one

名称	E/kJ	η/%	E_p/kJ•kg^-1	τ/min•kg^-1
情形1	6 120	36.7	4 066	10.6
情形2	7 200	37.5	2 478	8.6
情形3	11 880	28.5	2 825	13.3

表4 3种实验情形下的E、η、Ep和τ

Tab.4 E， η， Ep and τ in three experimental cases

参考文献 10

1	张惠敏.塑料旋转成型的特点与研究［J］.工程塑料应用，2002， 30 （4）： 23⁃26.
	ZHANG H M. Characteristics and study of rotational molding of plastics ［J］. Engineering Plastics Application， 2002， 30（4）：23⁃26.
2	GHOSH K， GARIMELLA S. Dynamic modeling of thermal processes in rotational molding ［C］. Proceedings of the ASME Heat Transfer/Fluids Engineering， Summer Conference， HT/FED 2004： 1 107⁃1 118.
3	WRIGHT M J， SPENCE A G， CRAWFORD R J. Analysis of heating efficiency in rotational moulding ［C］//Proceedings of the 1997 55th Annual Technical Conference， ANTEC， Toronto， Canada： Society of Plastics Engineers， 1997： 3 184⁃3 188.
4	MONZON M D， BORDON P， BENITEZ A N， et al. Global efficiency of innovative rotational mold directly heated by thermal fluid ［J］. Polymer Engineering and Science， 2012， 52（9）： 1 998⁃2 005.
5	MCDOWELL G W G， ORR J F， CRAWFORD R J， et al. The electric heating of moulds for the rotational moulding of plastics ［C］//35th Universities Power Engineering Conference， Belfast， United Kingdom： Technological Educational Institute， 2000： 94.
6	GOGOS G. Bubble removal in rotational molding ［J］. Polymer Engineering and Science， 2004， 44（2）： 388⁃394.
7	杨世铭，陶文铨.传热学［M］.北京：高等教育出版社，2006： 407⁃408，555⁃556.
8	郭同凯.旋转模塑过程的热交换计算机模拟系统［J］.新技术新工艺，1997（3）： 7⁃9.
	GUO T K. Computer⁃simulating system of heat transfer for rotational molding process ［J］. New Technology and Process， 1997（3）： 7⁃9.
9	GOGOS G， OLSON L G， LIU X J， et al. New models for rotational molding of plastics ［J］. Polymer Engineering and Science， 1998， 38（9）： 1 387⁃1 398.
10	CRAWFORD R J. Recent advances in the manufacture of plastic products by rotomoulding ［J］. Journal of Materials Processing Technology， 1996， 56（1）： 263⁃271.

[1]	叶冬蕾, 刘学军, 王晓. 滚塑工艺在加热阶段的两种传热模型的比较研究[J]. 中国塑料, 2022, 36(1): 114-119.
[2]	刘学军;江财明;朱国才. 滑梯形滚塑模具表面温度均匀性的数值研究[J]. 中国塑料, 2017, 31(6): 79-83 .
[3]	刘学军;贾丽亚. 滚塑工艺传热模型的研究进展[J]. 中国塑料, 2014, 28(06): 19-28 .
[4]	刘学军. 滚塑工艺成型周期的数值研究[J]. 中国塑料, 2013, 27(10): 58-64 .

直接电加热滚塑工艺的传热分析

Heat transfer analysis of rotational molding process heated directly with electricity

RichHTML

PDF

可视化

摘要/Abstract

引用本文

使用本文

图/表 10

参考文献 10

相关文章 4

编辑推荐

Metrics

本文评价