In today's education and teaching reform,the traditional teaching method in the teaching of polymer materials has been gradually replaced with various new teaching methods.Among them,the case analysis method is a ...In today's education and teaching reform,the traditional teaching method in the teaching of polymer materials has been gradually replaced with various new teaching methods.Among them,the case analysis method is a very efective teaching method,which has been applied to the teaching of polymer materials.Through example-based teaching,students 125 participation can be effectively improved,and their theoretical knowledge can be fully utilized.This would have a positive role in promoting the improvement of students'knowledge system and their learning ability.In regard to this,this article analyzes the application of case analysis in the teaching of polymer materials so as to improve its efficiency and quality.展开更多
This paper studied the thermal physical properties of foundation materials in the molten salt tank of thermal energy storage system after molten salt leakage by Transient plane source experiment and X-ray computed mic...This paper studied the thermal physical properties of foundation materials in the molten salt tank of thermal energy storage system after molten salt leakage by Transient plane source experiment and X-ray computed microtomography simulation methods.The microstructure,thermal properties and pressure resistance with different particle diameters were addressed.The measured heat conductivities from Transient plane source experiment for three cases are 0.49 W/(m·K),0.48 W/(m·K),and 0.51 W/(m·K),and the porosity is 30.1%,30.7%,and 31.2% respectively.The heat conductivity simulating results of three cases are 0.471 W/(m·K),0.482W/(m·K),and 0.513 W/(m·K).The ratio of difference between the results of simulation and Transient plane source measurement is as low as 1.2%,verifying the reliability of experimental and simulation results to a certain degree.Compared with the heat conductivity of 0.097-0.129 W/(m·K) and porosity of 71.6%-78.9% without leaking salt,the porosity is reduced by more than 50% while the heat conductivity increased by 4 to 5 times after molten salt leakage.This significant increase in heat conductivity has a great impact on security operation,structure design,and modeling of the tank foundation for solar power plants.展开更多
The free vibration characteristics of fluid-filled functionally graded cylindrical shells buried partially in elas- tic foundations are investigated by an analytical method. The elastic foundation of partial axial and...The free vibration characteristics of fluid-filled functionally graded cylindrical shells buried partially in elas- tic foundations are investigated by an analytical method. The elastic foundation of partial axial and angular dimen- sions is represented by the Pasternak model. The motion of the shells is represented by the first-order shear defor- mation theory to account for rotary inertia and transverse shear strains. The functionally graded cylindrical shells are composed of stainless steel and silicon nitride. Material prop- erties vary continuously through the thickness according to a power law distribution in terms of the volume fraction of the constituents. The governing equation is obtained using the Rayleigh-Ritz method and a variation approach. The fluid is described by the classical potential flow theory. Numerical examples are presented and compared with existing available results to validate the present method.展开更多
The leakage accident of molten salt in the thermal storage tank will cause the shutdown and enormous economic losses of Concentrated Solar Power plants.This study investigates the heat transfer and flow characteristic...The leakage accident of molten salt in the thermal storage tank will cause the shutdown and enormous economic losses of Concentrated Solar Power plants.This study investigates the heat transfer and flow characteristic of commercial molten nitrates leaking in the thermal state porous foundation material.The migration width and depth of three molten nitrates,Solar Salt(60 wt%NaNO_(3)-40 wt%KNO_(3)),Hitec XL(7 wt%NaNO_(3)-45 wt%KNO_(3)-48 wt%Ca(NO_(3))_(2))and Hitec(7 wt%NaNO_(3)-53 wt%KNO_(3)-40 wt%NaNO_(2)),are obtained at different operating temperatures.Experimental results indicate that the temperature rising rate of foundation material in the nitrate leaking process has a trend of first increasing rapidly and then decreasing,and then it increases slightly as the depth increases.The temperature rising rate increases obviously with increasing operating temperature of the molten salt.With the increase of the operating temperature,the distances from the storage tank bottom to solid salt in foundation and the total migration depths both increase obviously,while the average migrating widths change slightly.At the same operating temperature,the temperature rising rate of the foundation material where Hitec XL and Hitec salt leak is significantly greater than that with Solar Salt,which is closely related to the melting points of molten salts.The migration depth of Hitec is 95.03%greater than that of Solar Salt and 19.11%larger than that of Hitec XL at the operating temperature of 300℃.Compared with Hitec XL,the leakage of Hitec with a smaller viscosity has a larger temperature rising rate and a wider and deeper transporting range during the leakage process.This work could guide the installation locations of the leak detection devices for high temperature storage tank and the environmental treatment of leaking accident.展开更多
Molten salt is often used for heat transfer and thermal energy storage in concentrated solar power.Molten salt leakage and migration is a significant issue in its application.Molten salt migration and solidification i...Molten salt is often used for heat transfer and thermal energy storage in concentrated solar power.Molten salt leakage and migration is a significant issue in its application.Molten salt migration and solidification in thermal porous foundation materials through cracks are experimentally investigated.The impact of factors,including crack length and width,operation temperature,and leakage mass of molten salt,are studied through an experimental device modeling the leakage of the actual molten salt storage tank.Experimental results show that the crack width and length slightly affect the migration depth,but directly affect the shape of the agglomeration of solidified salt and porous foundation material.The most important factor affecting the migration depth of molten salt leaking through cracks is the tank operating temperature.The molten salt migration depth when the operating temperature is 500℃ is 95.8% higher than that with an operating temperature of 300℃.As the leakage molten salt mass reached 400 g,the average migration width increased by 23.6%,but the migration depth only increased by 5.2%.It is found that the foundation material temperatures after leakage accidents increase with an increase in the mass of leaked molten salt.展开更多
文摘In today's education and teaching reform,the traditional teaching method in the teaching of polymer materials has been gradually replaced with various new teaching methods.Among them,the case analysis method is a very efective teaching method,which has been applied to the teaching of polymer materials.Through example-based teaching,students 125 participation can be effectively improved,and their theoretical knowledge can be fully utilized.This would have a positive role in promoting the improvement of students'knowledge system and their learning ability.In regard to this,this article analyzes the application of case analysis in the teaching of polymer materials so as to improve its efficiency and quality.
基金supported by the National Natural Science Foundation of China (52036008)。
文摘This paper studied the thermal physical properties of foundation materials in the molten salt tank of thermal energy storage system after molten salt leakage by Transient plane source experiment and X-ray computed microtomography simulation methods.The microstructure,thermal properties and pressure resistance with different particle diameters were addressed.The measured heat conductivities from Transient plane source experiment for three cases are 0.49 W/(m·K),0.48 W/(m·K),and 0.51 W/(m·K),and the porosity is 30.1%,30.7%,and 31.2% respectively.The heat conductivity simulating results of three cases are 0.471 W/(m·K),0.482W/(m·K),and 0.513 W/(m·K).The ratio of difference between the results of simulation and Transient plane source measurement is as low as 1.2%,verifying the reliability of experimental and simulation results to a certain degree.Compared with the heat conductivity of 0.097-0.129 W/(m·K) and porosity of 71.6%-78.9% without leaking salt,the porosity is reduced by more than 50% while the heat conductivity increased by 4 to 5 times after molten salt leakage.This significant increase in heat conductivity has a great impact on security operation,structure design,and modeling of the tank foundation for solar power plants.
文摘The free vibration characteristics of fluid-filled functionally graded cylindrical shells buried partially in elas- tic foundations are investigated by an analytical method. The elastic foundation of partial axial and angular dimen- sions is represented by the Pasternak model. The motion of the shells is represented by the first-order shear defor- mation theory to account for rotary inertia and transverse shear strains. The functionally graded cylindrical shells are composed of stainless steel and silicon nitride. Material prop- erties vary continuously through the thickness according to a power law distribution in terms of the volume fraction of the constituents. The governing equation is obtained using the Rayleigh-Ritz method and a variation approach. The fluid is described by the classical potential flow theory. Numerical examples are presented and compared with existing available results to validate the present method.
基金This work was supported by the National Natural Science Foundation of China(52036008).
文摘The leakage accident of molten salt in the thermal storage tank will cause the shutdown and enormous economic losses of Concentrated Solar Power plants.This study investigates the heat transfer and flow characteristic of commercial molten nitrates leaking in the thermal state porous foundation material.The migration width and depth of three molten nitrates,Solar Salt(60 wt%NaNO_(3)-40 wt%KNO_(3)),Hitec XL(7 wt%NaNO_(3)-45 wt%KNO_(3)-48 wt%Ca(NO_(3))_(2))and Hitec(7 wt%NaNO_(3)-53 wt%KNO_(3)-40 wt%NaNO_(2)),are obtained at different operating temperatures.Experimental results indicate that the temperature rising rate of foundation material in the nitrate leaking process has a trend of first increasing rapidly and then decreasing,and then it increases slightly as the depth increases.The temperature rising rate increases obviously with increasing operating temperature of the molten salt.With the increase of the operating temperature,the distances from the storage tank bottom to solid salt in foundation and the total migration depths both increase obviously,while the average migrating widths change slightly.At the same operating temperature,the temperature rising rate of the foundation material where Hitec XL and Hitec salt leak is significantly greater than that with Solar Salt,which is closely related to the melting points of molten salts.The migration depth of Hitec is 95.03%greater than that of Solar Salt and 19.11%larger than that of Hitec XL at the operating temperature of 300℃.Compared with Hitec XL,the leakage of Hitec with a smaller viscosity has a larger temperature rising rate and a wider and deeper transporting range during the leakage process.This work could guide the installation locations of the leak detection devices for high temperature storage tank and the environmental treatment of leaking accident.
基金Project supported by the National Natural Science Foundation of China(No.52036008)。
文摘Molten salt is often used for heat transfer and thermal energy storage in concentrated solar power.Molten salt leakage and migration is a significant issue in its application.Molten salt migration and solidification in thermal porous foundation materials through cracks are experimentally investigated.The impact of factors,including crack length and width,operation temperature,and leakage mass of molten salt,are studied through an experimental device modeling the leakage of the actual molten salt storage tank.Experimental results show that the crack width and length slightly affect the migration depth,but directly affect the shape of the agglomeration of solidified salt and porous foundation material.The most important factor affecting the migration depth of molten salt leaking through cracks is the tank operating temperature.The molten salt migration depth when the operating temperature is 500℃ is 95.8% higher than that with an operating temperature of 300℃.As the leakage molten salt mass reached 400 g,the average migration width increased by 23.6%,but the migration depth only increased by 5.2%.It is found that the foundation material temperatures after leakage accidents increase with an increase in the mass of leaked molten salt.