The Joule–Thomson effect of (CO_(2)+H_(2)) binary system relevant to gas switching reforming with carbon capture and storage(CCS)

The Joule-Thomson effect is one of the important thermodynamic properties in the system relevant to gas switching reforming with carbon capture and storage(CCS). In this work, a set of apparatus was set up to determine the Joule-Thomson effect of binary mixtures(CO_(2)+ H_(2)). The accuracy of the apparatus was verified by comparing with the experimental data of carbon dioxide. The Joule-Thomson coefficients(μ_(JT)) for(CO_(2)+ H_(2)) binary mixtures with mole fractions of carbon dioxide(x_(CO_(2))= 0.1, 0.26, 0.5,0.86, 0.94) along six isotherms at various pressures were measured. Five equations of state EOSs(PR,SRK, PR, BWR and GERG-2008 equation) were used to calculate the μ_(JT)for both pure systems and binary systems, among which the GERG-2008 predicted best with a wide range of pressure and temperature.Moreover, the Joule-Thomson inversion curves(JTIC) were calculated with five equations of state. A comparison was made between experimental data and predicted data for the inversion curve of CO_(2). The investigated EOSs show a similar prediction of the low-temperature branch of the JTIC for both pure and binary systems, except for the BWRS equation of state. Among all the equations, SRK has the most similar result to GERG-2008 for predicting JTIC.

Temperature rise of He Ⅱ forced flow and its negative Joule-Thomson effect

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.

Effect of Spatial Dimension and External Potential on Joule-Thomson Coefficients of Ideal Bose Gases

Based on the form of the n-dimensional generic power-law potential, the state equation and the heat capacity,the analytical expressions of the Joule-Thomson coefficient (JTC) for an ideal Bose gas are derived in n-dimensionalpotential. The effect of the spatial dimension and the external potential on the JfC axe discussed, respectively. Theseresults show that: (ⅰ) For the free ideal Bose gas, when n/s ≤ 2 (n is the spatial dimension, s is the momentum indexin the relation between the energy and the momentum), and T →T_C (T_C is the critical temperature), the JTC canobviously improve by means of changing the throttle valve's shape and decreasing the spatial dimension of gases. (ⅱ)For the inhomogeneous external potential, the discriminant △= [1-∏_(i=1)~n (kT/ε_i)^(1/t_i) Γ(1/ti +1)] (κ is the BoltzmannConstant, T is the thermodynamic temperature, ε is the external field's energy), is obtained. The potential makes theJTC increase when △> 0, on the contrary, it makes the JTC decrease when △<0. (ⅲ) In the homogenous strongexternal potential, the JTC gets the maximum on the condition of κT/ε_i<<1.

超流氦的Joule-Thomson系数研究

超流氦的焦耳-汤姆逊系数在一定条件具有负值,且数值较大。由此产生的负焦耳-汤姆逊效应将会使其输送系统出现显著的温升,这一现象对于输送系统能否成功完成输送任务至关重要。如何确定He的Joule-Thomson系数,是判断He负焦耳-汤姆逊效应程度的前提和基础。文章通过直接状态方程法和热动力学公式法对He的Joule-Thomson系数进行了分析和计算,并在计算结果的基础上,拟合得到了便于工程应用的经验方程。

超流氦输送系统Joule-Thomson效应

通过直接状态方程法和热动力学公式法对HeⅡ的Joule-Thomson系数进行了分析和计算,并在计算结果的基础上,拟合得到了便于工程应用的经验方程.应用经典的紊流流动关联式和Fanning摩擦因子关系式对HeⅡ输送系统的压力损失进行了预测.利用系统的压力损失和Joule-Thomson系数分析并计算了由于负Joule-Thomson效应引发的系统温升.计算结果表明:应用状态方程法计算的结果与目前公开发表的应用热动力学公式的计算结果很接近;HeⅡ的流速和初始温度都会对最终的温升产生重要的影响.

费米气体的Joule-Thomson效应

应用热力学理论以及费米积分的特性 ,导出理想费米气体焦汤系数的解析表达式 ,详细讨论了低温下费米气体的定压热容和焦汤系数 ,并阐明了费米气体的量子本性对焦汤效应的影响 .结果表明理想费米气体的焦汤效应为负效应 .

双外场对费米气体Joule-Thomson效应的调控

研究匀强电场和谐振场构成的双外场对带电费米粒子系统化学势和Joule-Thomson系数的调控作用.在满足Thomas-Fermi近似的条件下,给出有限温度范围内匀强电场和谐振场中带电费米粒子系统的化学势和内能随温度变化的显式函数关系,分析双外场对带电费米粒子系统焦耳-汤姆逊系数的调控作用.研究结果表明,随着温度的升高,带电费米粒子系统的焦汤系数值逐渐由负变正,且临界温度Tc随外电场增强而降低.在适当温度下,外势场的存在会使带电费米粒子系统产生焦耳-汤姆逊正效应.

考虑Joule-Thomson效应的稳态热敏电阻问题

证明考虑 Joule- Thomson效应的稳态热敏电阻问题

Joule-Thomson inversion curve prediction by using equation of state

In this paper five equations of state are tested for checking their ability to predict the Joule-Thomson inversion curve.These five equations of state are:Mohsennia-Modarres-Mansoori(MMM),Ji-Lemp(JL),modified Soave-Redlich-Kwang(SRK)equation of state by Graboski(MSRK1),modified SRK equation of state by Peneloux and Rauzy(MSRK2),and modified Peng-Robinson (PR)equation of state by Rauzy(PRmr).The investigated equations of state give good prediction of the low-temperature branch of the inversion curve,except for MMM equation of state.The high-temperature branch and the peak of the inversion curve have been observed,in general,to be sensitive to the applied equation of state.The values of the maximum inversion temperature and maximum inversion pressure are calculated for each component used in this work.

Joule heating effect of electroosmosis in a finite-length microchannel made of different materials

This paper presents a numerical analysis of Joule heating effect of electroosmo- sis in a finite-length microchannel made of the glass and polydimethylsiloxane （PDMS） polymer. The Poisson-Boltzmann equation of electric double layer, the Navier-Stokes equation of liquid flow, and the liquid-solid coupled heat transfer equation are solved to investigate temperature behaviors of electroosmosis in a two-dimensional microchannel. The feedback effect of temperature variation on liquid properties （dielectric constant, vis- cosity, and thermal and electric conductivities） is taken into account. Numerical results indicate that there exists a heat developing length near the channel inlet where the flow velocity, temperature, pressure, and electric field rapidly vary and then approach to a steady state after the heat developing length, which may occupy a considerable portion of the microchannel in cases of thick chip and high electric field. The liquid temperature of steady state increases with the increase of the applied electric field, channel width, and chip thickness. The temperature on a PDMS wall is higher than that on a glass wall due to the difference of heat conductivities of materials. Temperature variations are found in the both longitudinal and transverse directions of the microchannel. The increase of the temperature on the wall decreases the charge density of the electric double layer. The longitudinal temperature variation induces a pressure gradient and changes the behavior of the electric field in the microchannel. The inflow liquid temperature does not change the liquid temperature of steady state and the heat developing length.

Joule-Thomson Coefficient for Strongly Interacting Unitary Fermi Gas

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.

Effect of Joule heating on the electroosmotic microvortex and dielectrophoretic particle separation controlled by local electric field

Dielectrophoresis(DEP)technology has become important application of microfluidic technology to manipulate particles.By using a local modulating electric field to control the combination of electroosmotic microvortices and DEP,our group proposed a device using a direct current(DC)electric field to achieve continuous particle separation.In this paper,the influence of the Joule heating effect on the continuous separation of particles is analyzed.Results show that the Joule heating effect is caused by the local electric field,and the Joule heating effect caused by adjusting the modulating voltage is more significant than that by driving voltage.Moreover,a non-uniform temperature distribution exists in the channel due to the Joule heating effect,and the temperature is the highest at the midpoint of the modulating electrodes.The channel flux can be enhanced,and the enhancement of both the channel flux and temperature is more obvious for a stronger Joule heating effect.In addition,the ability of the vortices to trap particles is enhanced since a larger DEP force is exerted on the particles with the Joule heating effect;and the ability of the vortex to capture particles is stronger with a stronger Joule heating effect.The separation efficiency can also be increased because perfect separation is achieved at a higher channel flux.Parameter optimization of the separation device,such as the convective heat transfer coefficient of the channel wall,the length of modulating electrode,and the width of the channel,is performed.

Thomson and rotation effects during photothermal excitation process in magnetic semiconductor medium using variable thermal conductivity

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.

Influence of heating effect in Thomson scattering diagnosis of laser-produced plasmas in air

A state diagnosis of laser-produced plasma in air generated by a 1064 nm pulse laser was investigated by the Thomson scattering(TS)method.The evolutions of the electron temperature and electron density were obtained as a function of the time delay which ranged from 300-3200 ns.The heating effect produced by the 532 nm probe beam with different energies on the air plasma at different interaction times was further studied using a time-resolved optical emission spectroscopy technique.The influence of the probe beam on the electron density was found to be negligible,whereas its influence on electron temperature is evident.In addition,the heating effect of the probe beam on the plasma strongly depends on the energy of the probe beam,and gradually weakens with increasing time delay.Our results are helpful for further understanding the TS method and its application in plasma diagnostics.

冷冻活检针中CO_(2)节流降温特性的实验研究

通过对比不同CO_(2)进气压力下4款冷冻活检针中的降温特性,分析进气压力、J-T槽内径、回流通道大小对于活检针降温的影响,并测试其在明胶中形成的冰球大小。结果表明:1.8-0.42 mm、1.8-0.30 mm、1.8-0.12 mm、1.1 mm活检针分别在4.5、4.0、5.5、5.5 MPa的进气压力下降温最快。压力较小时,降温速率与进气压力呈正相关,进气压力大于最佳压力值时,随着压力增大,冰堵加剧;测试的活检针中,较小的J-T槽内径有利于提高活检针的降温速率以及获得更低的刀头温度,较大的回流通道可以减少管内冰堵,提高降温速率;1.8-0.42 mm、1.8-0.30 mm、1.8-0.12 mm、1.1 mm活检针分别在4.5、4.5、6.0、6.0 MPa气源压力下冰球直径最大,当J-T槽的内径减小时,其最佳的气源压力有所增大。

Electrifying Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-δ) for focalized heating in oxygen transport membranes

Industry decarbonization requires the development of highly efficient and flexible technologies relying on renewable energy resources,especially biomass and solar/wind electricity.In the case of pure oxygen production,oxygen transport membranes(OTMs)appear as an alternative technology for the cryogenic distillation of air,the industrially-established process of producing oxygen.Moreover,OTMs could provide oxygen from different sources(air,water,CO_(2),etc.),and they are more flexible in adapting to current processes,producing oxygen at 700^(-1)000℃.Furthermore,OTMs can be integrated into catalytic membrane reactors,providing new pathways for different processes.The first part of this study was focused on electrification on a traditional OTM material(Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-δ)),imposing different electric currents/voltages along a capillary membrane.Thanks to the emerging Joule effect,the membrane-surface temperature and the associated O_(2) permeation flux could be adjusted.Here,the OTM is electrically and locally heated and reaches 900℃on the surface,whereas the surrounding of the membrane was maintained at 650℃.The O_(2)permeation flux reached for the electrified membranes was~3.7 NmL min^(-1)cm^(-2),corresponding to the flux obtained with an OTM non-electrified at 900℃.The influence of depositing a porous Ce_(0.8)Tb_(0.2)O_(2-δ) catalytic/protective layer on the outer membrane surface revealed that lower surface temperatures(830℃)were detected at the same imposed electric power.Finally,the electrification concept was demonstrated in a catalytic membrane reactor(CMR)where the oxidative dehydrogenation of ethane(ODHE)was carried out.ODHE reaction is very sensitive to temperature,and here,we demonstrate an improvement of the ethylene yield by reaching moderate temperatures in the reaction chamber while the O_(2) injection into the reaction can be easily fine-tuned.

橡胶热拉伸应力测量与影响因素研究

拉伸状态橡胶材料受热产生“收缩”现象,对应样品尺寸与热拉伸应力同步变化,影响橡胶制品的使用性能。文章通过硫化橡胶热拉伸应力测试,研究了硫化橡胶热拉伸应力与样品尺寸变化联系,并探讨了热拉伸应力随测试温度、升温速率、拉伸应变等条件的变化规律。

铂电阻温度计自热效应对测量结果的影响

在流体测量和控制中,温度是一个关键参数,直接影响流体的密度和黏度。铂电阻温度计因精确度和稳定性较高而被广泛应用,但其自热效应可能导致测量误差。该自热效应会引起额外的热量,使流体的温度发生变化,进而影响流体的密度、黏度、流动状态等属性。本文探讨了自热效应的机理,特别是电流通过铂电阻时产生的焦耳热及对测量结果的影响。针对流体的特性,对如何选择合适的铂电阻温度计,以及如何实施相应的自热效应校正方法进行深入探讨。通过了解流体性质、选择合适的温度计型号,并采用先进的补偿技术,可以最大限度地减少自热效应对测量结果的影响。

Effect of an electrostatic field on gas adsorption and diffusion in tectonic coal

The characteristics of adsorption, desorption, and diffusion of gas in tectonic coal are important for the prediction of coal and gas outbursts. Three types of coal samples, of which both metamorphic grade and degree of damage is different, were selected from Tongchun, Qilin, and Pingdingshan mines. Using a series of experiments in an electrostatic field, we analyzed the characteristics of gas adsorption and diffusion in tectonic coal. We found that gas adsorption in coal conforms to the Langmuir equation in an electrostatic field. Both the depth of the adsorption potential well and the coal molecular electronegativity increases under the action of an electrostatic field. A Joule heating effect was caused by changing the coal–gas system conductivity in an electrostatic field. The quantity of gas adsorbed and DP result from competition between the depth of the adsorption potential well, the coal molecular electronegativity, and the Joule heating effect. DP peaks when the three factors control behavior equally. Compared with anthracite, the impact of the electrostatic field on the gas diffusion capacity of middle and high rank coals is greater. Compared with the original coal, the gas adsorption quantity, DP, and the gas diffusion capacity of tectonic coal are greater in an electrostatic field. In addition, the smaller the particle size of tectonic coal, the larger the DP.

Relativistic correction of （v/c）2 to the collective Thomson scattering for high-temperature high-density plasma

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.