The temperature rise of He Ⅱ transfer system due to the negative Joule-Thomson(JT)effect is one of the major problems in the He Ⅱ forced flow system design.Negative Joule-Thomson effect of the He Ⅱ forced flow was ...The temperature rise of He Ⅱ transfer system due to the negative Joule-Thomson(JT)effect is one of the major problems in the He Ⅱ forced flow system design.Negative Joule-Thomson effect of the He Ⅱ forced flow was analyzed and calculated in this paper.The temperature rise due to the heat leak along the transfer pipeline was calculated by the simplified equation and was modified by considering the negative Joule-Thomson effect.The modified results were compared with the temperature rise obtained by non-linear differential equations with consideration of the pressure gradient.The results show that the pressure gradient has strong effect on the temperature distribution.The modified results are in good agreement with the values calculated by the complicated equation,which verifies the effectiveness of the simplified equation in calculating the temperature rise when the negative JT effect of He Ⅱ is known.展开更多
This study investigates a strong magnetic field acting over an elastic rotator semiconductor medium.The Thomson effect due to the magnetic field during the photothermal transport process is studied,and the thermoelect...This study investigates a strong magnetic field acting over an elastic rotator semiconductor medium.The Thomson effect due to the magnetic field during the photothermal transport process is studied,and the thermoelectricity theory is used to explain the behavior of waves in the homogenous and isotropic medium under the effect of variable thermal conductivity.The variable thermal conductivity is considered as a linear function of the temperature.The two-dimensional deformation equations are used to describe the overlaps among plasma,electrical,thermal,and magneto-elastic waves.The charge density of inertia-particles is considered as a function of time for studying the induced electric current.The normal mode analysis is used to obtain the exact solutions of the physical field distributions as part of this phenomenon.To obtain the complete solutions of the physical field quantities,the certain mechanical loads,electromagnetic effects,thermal effects,and plasma recombination process are applied herein.The results of the physical distributions are graphically depicted and discussed in consideration of the internal heat source,rotation,and Peltier coefficient.展开更多
The present investigation deals with the 2-dimensional deformation in a homogeneous thermoelastic solid with voids subjected to inclined loads.The heat conduction equation is affected with the Thomson coefficient.The ...The present investigation deals with the 2-dimensional deformation in a homogeneous thermoelastic solid with voids subjected to inclined loads.The heat conduction equation is affected with the Thomson coefficient.The basic governing equations are modified by using Green-Naghdi theory of type-III.The normal mode analysis technique is used to obtain the components of stress,strain,temperature,induced magnetic field and change in volume fraction field.The variations of these quantities have been depicted graphically in the Green-Naghdi theories of type-II and III for an insulated boundary.From numerical calculations,the effect of Thomson parameter and angle of inclination on a homogeneous,isotropic,electro-magneto-thermoelastic material with voids is revealed and discussed.展开更多
In this paper,a one-dimensional thermodynamic model was developed to evaluate the device-level performance of thermoelectric cooler(TEC)with the Thomson effect,contact resistance,gap heat leakage,heat sink,and heat lo...In this paper,a one-dimensional thermodynamic model was developed to evaluate the device-level performance of thermoelectric cooler(TEC)with the Thomson effect,contact resistance,gap heat leakage,heat sink,and heat load taken into account.The model was generalized and simplified by introducing dimensionless parameters.Experimental measurements showed good agreement with analytical results.The parametric analysis indicated that the influence of the Thomson effect on cooling capacity continued to expand with increasing current,while the effect on COP hardly changed with current.Low thermal contact resistance was beneficial to obtain lower hot-junction temperature,which can even reduce 2 K compared with the electrical contact resistance in the case study.The gap heat leakage was a negative factor affecting the cooling performance.When the thermal resistance of the heat sink was small,the negative effect of heat leakage on performance would be further enlarged.The enhancement of heat load temperature would increase the cooling power of the TEC.For example,an increase of 5 K in heat load can increase the cooling capacity by about 4%.However,once the current exceeded the optimum value,the raising effect on the cooling power would be weakened.The research can provide an analytical approach for the designer to perform trade studies to optimize the TEC system.展开更多
Collective Thomson scattering is theoretically investigated with the inclusion of the relativistic correction of (v/c)2. The correction is rather small for the plasma parameters inferred from the spectra of the ther...Collective Thomson scattering is theoretically investigated with the inclusion of the relativistic correction of (v/c)2. The correction is rather small for the plasma parameters inferred from the spectra of the thermal electron plasma waves in the plasma. Since the full formula of the corrected result is rather complicated, a simplified one is derived for practical use, which is shown to be in good agreement with the un-simplified one.展开更多
The Joule-Thomson effect reflects the interaction among constituent particles of macroscopic system.Forclassical ideal gas,the corresponding Joule-Thomson coefficient is vanishing while it is non-zero for ideal quantu...The Joule-Thomson effect reflects the interaction among constituent particles of macroscopic system.Forclassical ideal gas,the corresponding Joule-Thomson coefficient is vanishing while it is non-zero for ideal quantum gasdue to the quantum degeneracy.In recent years,much attention is paid to the unitary Fermi gas with infinite two-bodyscattering length.According to universal analysis,the thermodynamical law of unitary Fermi gas is similar to that ofnon-interacting ideal gas,which can be explored by the virial theorem P = 2E/3V.Based on previous works,we furtherstudy the unitary Fermi gas properties.The effective chemical potential is introduced to characterize the nonlinear levelscrossing effects in a strongly interacting medium.The changing behavior of the rescaled Joule-Thomson coefficientaccording to temperature manifests a quite different behavior from that for ideal Fermi gas.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.10872152)the Ministries and Commissions of Science and Technology of Shanghai Government (Grant No. 03DZ 14014) for Shanghai Jiaotong University
文摘The temperature rise of He Ⅱ transfer system due to the negative Joule-Thomson(JT)effect is one of the major problems in the He Ⅱ forced flow system design.Negative Joule-Thomson effect of the He Ⅱ forced flow was analyzed and calculated in this paper.The temperature rise due to the heat leak along the transfer pipeline was calculated by the simplified equation and was modified by considering the negative Joule-Thomson effect.The modified results were compared with the temperature rise obtained by non-linear differential equations with consideration of the pressure gradient.The results show that the pressure gradient has strong effect on the temperature distribution.The modified results are in good agreement with the values calculated by the complicated equation,which verifies the effectiveness of the simplified equation in calculating the temperature rise when the negative JT effect of He Ⅱ is known.
文摘This study investigates a strong magnetic field acting over an elastic rotator semiconductor medium.The Thomson effect due to the magnetic field during the photothermal transport process is studied,and the thermoelectricity theory is used to explain the behavior of waves in the homogenous and isotropic medium under the effect of variable thermal conductivity.The variable thermal conductivity is considered as a linear function of the temperature.The two-dimensional deformation equations are used to describe the overlaps among plasma,electrical,thermal,and magneto-elastic waves.The charge density of inertia-particles is considered as a function of time for studying the induced electric current.The normal mode analysis is used to obtain the exact solutions of the physical field distributions as part of this phenomenon.To obtain the complete solutions of the physical field quantities,the certain mechanical loads,electromagnetic effects,thermal effects,and plasma recombination process are applied herein.The results of the physical distributions are graphically depicted and discussed in consideration of the internal heat source,rotation,and Peltier coefficient.
文摘The present investigation deals with the 2-dimensional deformation in a homogeneous thermoelastic solid with voids subjected to inclined loads.The heat conduction equation is affected with the Thomson coefficient.The basic governing equations are modified by using Green-Naghdi theory of type-III.The normal mode analysis technique is used to obtain the components of stress,strain,temperature,induced magnetic field and change in volume fraction field.The variations of these quantities have been depicted graphically in the Green-Naghdi theories of type-II and III for an insulated boundary.From numerical calculations,the effect of Thomson parameter and angle of inclination on a homogeneous,isotropic,electro-magneto-thermoelastic material with voids is revealed and discussed.
基金financially supported by the National Natural Science Foundation of China(NSFC)(Grant No.52106032)the Science Challenge Program(Grant No.TZ2018003)+2 种基金the National Natural Science Foundation of China(Grant No.51778511)the Hubei Provincial Natural Science Foundation of China(Grant No.2018CFA029)the Key Project of ESI Discipline Development of Wuhan University of Technology(WUT Grant No.2017001)。
文摘In this paper,a one-dimensional thermodynamic model was developed to evaluate the device-level performance of thermoelectric cooler(TEC)with the Thomson effect,contact resistance,gap heat leakage,heat sink,and heat load taken into account.The model was generalized and simplified by introducing dimensionless parameters.Experimental measurements showed good agreement with analytical results.The parametric analysis indicated that the influence of the Thomson effect on cooling capacity continued to expand with increasing current,while the effect on COP hardly changed with current.Low thermal contact resistance was beneficial to obtain lower hot-junction temperature,which can even reduce 2 K compared with the electrical contact resistance in the case study.The gap heat leakage was a negative factor affecting the cooling performance.When the thermal resistance of the heat sink was small,the negative effect of heat leakage on performance would be further enlarged.The enhancement of heat load temperature would increase the cooling power of the TEC.For example,an increase of 5 K in heat load can increase the cooling capacity by about 4%.However,once the current exceeded the optimum value,the raising effect on the cooling power would be weakened.The research can provide an analytical approach for the designer to perform trade studies to optimize the TEC system.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.10625523 and 11005112)the Innovative Project of Chinese Academy of Sciences (Grant No.KJCX2-YW-N36)
文摘Collective Thomson scattering is theoretically investigated with the inclusion of the relativistic correction of (v/c)2. The correction is rather small for the plasma parameters inferred from the spectra of the thermal electron plasma waves in the plasma. Since the full formula of the corrected result is rather complicated, a simplified one is derived for practical use, which is shown to be in good agreement with the un-simplified one.
基金Supported in part by Natural Science Foundation of China under Grant Nos.10875050,10675052MOE of China under Grant No.IRT0624
文摘The Joule-Thomson effect reflects the interaction among constituent particles of macroscopic system.Forclassical ideal gas,the corresponding Joule-Thomson coefficient is vanishing while it is non-zero for ideal quantum gasdue to the quantum degeneracy.In recent years,much attention is paid to the unitary Fermi gas with infinite two-bodyscattering length.According to universal analysis,the thermodynamical law of unitary Fermi gas is similar to that ofnon-interacting ideal gas,which can be explored by the virial theorem P = 2E/3V.Based on previous works,we furtherstudy the unitary Fermi gas properties.The effective chemical potential is introduced to characterize the nonlinear levelscrossing effects in a strongly interacting medium.The changing behavior of the rescaled Joule-Thomson coefficientaccording to temperature manifests a quite different behavior from that for ideal Fermi gas.