A hybrid identification model based on multilayer artificial neural networks(ANNs) and particle swarm optimization(PSO) algorithm is developed to improve the simultaneous identification efficiency of thermal conductiv...A hybrid identification model based on multilayer artificial neural networks(ANNs) and particle swarm optimization(PSO) algorithm is developed to improve the simultaneous identification efficiency of thermal conductivity and effective absorption coefficient of semitransparent materials.For the direct model,the spherical harmonic method and the finite volume method are used to solve the coupled conduction-radiation heat transfer problem in an absorbing,emitting,and non-scattering 2D axisymmetric gray medium in the background of laser flash method.For the identification part,firstly,the temperature field and the incident radiation field in different positions are chosen as observables.Then,a traditional identification model based on PSO algorithm is established.Finally,multilayer ANNs are built to fit and replace the direct model in the traditional identification model to speed up the identification process.The results show that compared with the traditional identification model,the time cost of the hybrid identification model is reduced by about 1 000 times.Besides,the hybrid identification model remains a high level of accuracy even with measurement errors.展开更多
The transient coupled radiative and conductive heat transfer in a semitransparent composite under the complexboundary conditidns is investigated by the ray tracing method in combination with Hottel’s zonal method and...The transient coupled radiative and conductive heat transfer in a semitransparent composite under the complexboundary conditidns is investigated by the ray tracing method in combination with Hottel’s zonal method and thecontrol-volume method. The composite is composed of tWo plane layers of nonscattering sendtransparent media withthe different thermophysical Properties in each layer. Both boundals surfaces and the internal interface aresemitransparent. The reflections are assUmed diffuse or specular. The transient temperature distributions in thecomposite are Obtained for the combined thermal boundary conditions of incident radiation and convective heat transfer.Under diffuse reflection, the resultS in this paper are separately compared with the steady and transient results ofPrevious work. The comparison shows the reliability and the high calculating accuracy of the formulas derived in thespaper. The Present analysis includes the effeCts of the optical thickness, the conduchon-radiation parameter, the spectralproperty and the renechve mode on the transient temperature distributions.展开更多
基金supported by the Fundamental Research Funds for the Central Universities (No.3122020072)the Multi-investment Project of Tianjin Applied Basic Research(No.23JCQNJC00250)。
文摘A hybrid identification model based on multilayer artificial neural networks(ANNs) and particle swarm optimization(PSO) algorithm is developed to improve the simultaneous identification efficiency of thermal conductivity and effective absorption coefficient of semitransparent materials.For the direct model,the spherical harmonic method and the finite volume method are used to solve the coupled conduction-radiation heat transfer problem in an absorbing,emitting,and non-scattering 2D axisymmetric gray medium in the background of laser flash method.For the identification part,firstly,the temperature field and the incident radiation field in different positions are chosen as observables.Then,a traditional identification model based on PSO algorithm is established.Finally,multilayer ANNs are built to fit and replace the direct model in the traditional identification model to speed up the identification process.The results show that compared with the traditional identification model,the time cost of the hybrid identification model is reduced by about 1 000 times.Besides,the hybrid identification model remains a high level of accuracy even with measurement errors.
文摘The transient coupled radiative and conductive heat transfer in a semitransparent composite under the complexboundary conditidns is investigated by the ray tracing method in combination with Hottel’s zonal method and thecontrol-volume method. The composite is composed of tWo plane layers of nonscattering sendtransparent media withthe different thermophysical Properties in each layer. Both boundals surfaces and the internal interface aresemitransparent. The reflections are assUmed diffuse or specular. The transient temperature distributions in thecomposite are Obtained for the combined thermal boundary conditions of incident radiation and convective heat transfer.Under diffuse reflection, the resultS in this paper are separately compared with the steady and transient results ofPrevious work. The comparison shows the reliability and the high calculating accuracy of the formulas derived in thespaper. The Present analysis includes the effeCts of the optical thickness, the conduchon-radiation parameter, the spectralproperty and the renechve mode on the transient temperature distributions.
