螺杆熔融段构型对传热效率的影响
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摘要
采用数值模拟的方法,对比了普通的和分别放置扭转元件、Maddock元件的螺杆熔融段处的传热效率,并从流体速度场和温度梯度场的协同性解释差异产生的原因。模拟结果表明,扭转元件的特殊流道设计能够有效提高流道内速度场和温度梯度场的协同性,显著增强对流传热,无论元件放置在熔融段的入口还是出口,装有扭转元件的螺杆的传热效率都远远高于装有Maddock元件的螺杆和纯螺纹螺杆;同时,扭转元件对物料的剪切力相对Maddock元件小得多,从而使螺杆产生的黏性耗散热降低,局部过热的现象得到很好的控制。从模拟结果来看,场协同理论的结果与模拟的实际结果具有良好的一致性,因此场协同理论可以用于解释聚合物加工中高黏度非牛顿流体的传热特性。
Numerical simulation was used to compare the heat transfer efficiency of general screw and the screws assembled with torsion element and Maddock element at compression zone.Reasons of the differences were proposed from the viewpoint of the synergy of velocity field and temperature gradient field.Simulation results showed that the torsion element with elaborately designed flow channel would effectively improve the synergy of velocity field and temperature gradient field,significantly enhancing the convective heat transfer.Heat transfer efficiency of screws assembled with torsion element were much higher than those with Maddock element and general screw,no matter on the inlet or outlet of compression zone.At the same time,the torsion element applied much less shear stress compare to Maddock element.Thus,the heat caused by viscous dissipation would reduce significantly and local overheating phenomenon could be well-controlled.Moreover,the results obtained from field synergy theory were consistent with the actual simulation results,so field synergy theory could be used to explain the heat transfer properties of non-newtonian fluid with high viscosity in polymer processing.
Numerical simulation was used to compare the heat transfer efficiency of general screw and the screws assembled with torsion element and Maddock element at compression zone.Reasons of the differences were proposed from the viewpoint of the synergy of velocity field and temperature gradient field.Simulation results showed that the torsion element with elaborately designed flow channel would effectively improve the synergy of velocity field and temperature gradient field,significantly enhancing the convective heat transfer.Heat transfer efficiency of screws assembled with torsion element were much higher than those with Maddock element and general screw,no matter on the inlet or outlet of compression zone.At the same time,the torsion element applied much less shear stress compare to Maddock element.Thus,the heat caused by viscous dissipation would reduce significantly and local overheating phenomenon could be well-controlled.Moreover,the results obtained from field synergy theory were consistent with the actual simulation results,so field synergy theory could be used to explain the heat transfer properties of non-newtonian fluid with high viscosity in polymer processing.
引文
[1]李建立,陈均尉.聚合物熔融机理实验研究现状[J].工程塑料应用,2013,41(10):105-109.
[2]Tadmor Z.Principles of polymer processing[M].Beijing:Chemical Industry Press,2009.
[3]朱春雁.Maddock元件的混合性能的理论分析[J].大连工业大学学报,1987(1):17-23.
[4]高岗,谢林生,马玉录,等.不同结构单螺杆屏障混炼元件混合特性研究[J].中国塑料,2015,29(9):85-91.
[5]Guo Z Y,Li D Y,Wang B X.A novel noncept for convective heat transfer enhancement[J].International Journal of Heat&Mass Transfer,1998,41(14):2 221-2 225.
[6]Zeng M,Tao W Q.Numerical verification of the field synergy principle for turbulent flow[J].Journal of Enhanced Heat Transfer,2004,11(4):453-460.
[7]Tao W Q,He Y L,Qu Z G,et al.Applications of the field synergy principle in developing new type heat transfer enhanced surfaces[J].Journal of Enhanced Heat Transfer,2004,11(4):435-452.
[8]何雅玲,雷勇刚,田丽亭,等.高效低阻强化换热技术的三场协同性探讨[J].工程热物理学报,2009,30(11):1 904-1 906.
[9]杨志超,杨臧健,钟英杰.场协同理论及其在脉动流传热技术中的应用前景[J].机电工程,2013,30(4):435-438.
[10]杨卫民.高分子材料先进制造的微积分思想[J].中国塑料,2010,24(7):1-6.
[11]丁玉梅,鉴冉冉,焦志伟,等.聚合物熔体微积分强化传热与混炼塑化挤出机:中国,2014100070682[P].2014-04-30.
[12]鉴冉冉,谭伟华,谢鹏程,等.新型扭转元件塑化过程冷态可视化试验[J].塑料,2017,46(5):53-55.
[13]鉴冉冉,谢鹏程,丁玉梅,等.新型扭转元件塑化过程数值模拟[J].塑料,2016,45(5):9-13.
[14]鉴冉冉,谢鹏程,杨卫民.基于场协同原理的聚合物塑化过程数值分析[J].工程热物理学报,2017,38(2):281-288.
[15]赵世超,杨卫民,鉴冉冉,等.新型场协同螺杆元件强化传质实验[J].塑料,2017,46(6):88-91.
[16]Jian R R,Yang W M,Cheng L S,et al.Numerical analysis of enhanced heat transfer by incorporating torsion elements in the homogenizing section of polymer plasticization with the field synergy principle[J].International Journal of Heat&Mass Transfer,2017,115:946-953.
[17]梁畅.同向双螺杆挤出机熔融段熔融传热过程研究[D].北京:北京化工大学,2012.
[18]Inc F.Fluent user's guide[M/CD].Fluent Inc,2003.
[19]李志信,过增元.对流传热优化的场协同理论[M].北京:科学出版社,2010.
[20]Guo Z Y,Tao W Q,Shah R K.The field synergy(coordination)principle and its applications in enhancing single phase convective heat transfer[J].International Journal of Heat&Mass Transfer,2005,48(9):1 797-1 807.
[21]周俊杰,陶文铨,王定标.场协同原理评价指标的定性分析和定量探讨[J].郑州大学学报:工学版,2006,27(2):45-47.
[2]Tadmor Z.Principles of polymer processing[M].Beijing:Chemical Industry Press,2009.
[3]朱春雁.Maddock元件的混合性能的理论分析[J].大连工业大学学报,1987(1):17-23.
[4]高岗,谢林生,马玉录,等.不同结构单螺杆屏障混炼元件混合特性研究[J].中国塑料,2015,29(9):85-91.
[5]Guo Z Y,Li D Y,Wang B X.A novel noncept for convective heat transfer enhancement[J].International Journal of Heat&Mass Transfer,1998,41(14):2 221-2 225.
[6]Zeng M,Tao W Q.Numerical verification of the field synergy principle for turbulent flow[J].Journal of Enhanced Heat Transfer,2004,11(4):453-460.
[7]Tao W Q,He Y L,Qu Z G,et al.Applications of the field synergy principle in developing new type heat transfer enhanced surfaces[J].Journal of Enhanced Heat Transfer,2004,11(4):435-452.
[8]何雅玲,雷勇刚,田丽亭,等.高效低阻强化换热技术的三场协同性探讨[J].工程热物理学报,2009,30(11):1 904-1 906.
[9]杨志超,杨臧健,钟英杰.场协同理论及其在脉动流传热技术中的应用前景[J].机电工程,2013,30(4):435-438.
[10]杨卫民.高分子材料先进制造的微积分思想[J].中国塑料,2010,24(7):1-6.
[11]丁玉梅,鉴冉冉,焦志伟,等.聚合物熔体微积分强化传热与混炼塑化挤出机:中国,2014100070682[P].2014-04-30.
[12]鉴冉冉,谭伟华,谢鹏程,等.新型扭转元件塑化过程冷态可视化试验[J].塑料,2017,46(5):53-55.
[13]鉴冉冉,谢鹏程,丁玉梅,等.新型扭转元件塑化过程数值模拟[J].塑料,2016,45(5):9-13.
[14]鉴冉冉,谢鹏程,杨卫民.基于场协同原理的聚合物塑化过程数值分析[J].工程热物理学报,2017,38(2):281-288.
[15]赵世超,杨卫民,鉴冉冉,等.新型场协同螺杆元件强化传质实验[J].塑料,2017,46(6):88-91.
[16]Jian R R,Yang W M,Cheng L S,et al.Numerical analysis of enhanced heat transfer by incorporating torsion elements in the homogenizing section of polymer plasticization with the field synergy principle[J].International Journal of Heat&Mass Transfer,2017,115:946-953.
[17]梁畅.同向双螺杆挤出机熔融段熔融传热过程研究[D].北京:北京化工大学,2012.
[18]Inc F.Fluent user's guide[M/CD].Fluent Inc,2003.
[19]李志信,过增元.对流传热优化的场协同理论[M].北京:科学出版社,2010.
[20]Guo Z Y,Tao W Q,Shah R K.The field synergy(coordination)principle and its applications in enhancing single phase convective heat transfer[J].International Journal of Heat&Mass Transfer,2005,48(9):1 797-1 807.
[21]周俊杰,陶文铨,王定标.场协同原理评价指标的定性分析和定量探讨[J].郑州大学学报:工学版,2006,27(2):45-47.