Transmission Loss (TL) of a glass cylinder tube containing a fluid is studied experimentally. This test specimen represents a typical double layer panel including a fluid. The tests are carried out by using a modified...Transmission Loss (TL) of a glass cylinder tube containing a fluid is studied experimentally. This test specimen represents a typical double layer panel including a fluid. The tests are carried out by using a modified four-microphone standing-wave (impedance) tube for specimens with different lengths, 15 and 30 mm. Each cylinder tube is tested filled with one of the fluids at a time. The fluids are air, water, motor oil and a nanoparticle fluid (in absence of magnetic field). The effects of the cylinder length (thickness), impedance tube terminations, and the containing fluid are discussed. The increasing of the thickness led to an increase of the TL values and a decrease in resonance frequencies. Also, the addition of liquid middle layer led to considerable increase of the TL.展开更多
Evaporation loss from the saturated soil beneath drip irrigation emitters highly influences the irrigation efficiency of drip krigation （D1]. Subsurface drip irrigation （SDI） is one good approach to curb this ineff...Evaporation loss from the saturated soil beneath drip irrigation emitters highly influences the irrigation efficiency of drip krigation （D1]. Subsurface drip irrigation （SDI） is one good approach to curb this inefficiency, but in a new irrigation method, straight tube irrigation （STI）, the irrigation tubes do not need to be buried and thus STI is recommended to increase the irrigation efficiency under normal surface-applied DI. STI consists of only connectors and water-transference tubes that can directly transfer irrigation water from the lateral emitters in the drip line to the root zone of plants. Five-month field experiments were carried out in aeolian sand soil in the forest-belts of the Taklimakan Desert, which have poor water storage capacity, to compare the potential water saving between STI and DI. The preliminary results showed that, compared with DI, STI （1） improved the soil water content in soil depths from 40 to 100 cm under the soil surface; （2） achieved the same irrigation effects in relatively shorter irrigation durations; （3） had very little water loss due to deep seepage; and （4） formed a layer of dry sand about 10 to 30 cm thick immediately below the soil surface, which lessened evaporation loss of soil water beneath the emitters on the soil surface. This demonstrates that STI can maximize the water-saving potential of DI through the reduction of wetted soil perimeters on the soil surface. This is valuable information for water-saving engineering applications and projects with STI in arid and semiarid regions.展开更多
The shock tubes with area change are used in the free piston shock tunnels,owing to its higher driver effect.For optimized operation of this kind of shock tube,a computer program for fast simulation of transient hyper...The shock tubes with area change are used in the free piston shock tunnels,owing to its higher driver effect.For optimized operation of this kind of shock tube,a computer program for fast simulation of transient hypersonic flow is presented.The numerical modeling embodied within this code is based on a quasi-one-dimensional Lagrangian description of the gas dynamics.In this code,a mass-loss model is also applied by using Mirels′theory of shock attenuation.The simulation of particular condition for T4 free piston shock tunnel is conducted and compared with experimental measurements and numerical simulation.The results provide good estimate for shock speed and pressure obtained after shock reflection.展开更多
To improve the utilization efficiency of water the laying length of porous tubes was analyzed. Considering long porous tubes the irrigation uniformity of porous tubes was studied by analyzing the deviation rate of the...To improve the utilization efficiency of water the laying length of porous tubes was analyzed. Considering long porous tubes the irrigation uniformity of porous tubes was studied by analyzing the deviation rate of the working head of porous tubes and through an impact analysis of the deviation ratio of flow rate based on laying length slope pressure head and perforation spacing. Results showed that the deviation ratio of the flow rate could be reduced by decreasing the length of tubes and increasing the slope. The deviation ratio of flow rate was less influenced by pressure head and perforation spacing. A best laid slope resulted in a longer laying length of the porous tubes and they were not constant.展开更多
文摘Transmission Loss (TL) of a glass cylinder tube containing a fluid is studied experimentally. This test specimen represents a typical double layer panel including a fluid. The tests are carried out by using a modified four-microphone standing-wave (impedance) tube for specimens with different lengths, 15 and 30 mm. Each cylinder tube is tested filled with one of the fluids at a time. The fluids are air, water, motor oil and a nanoparticle fluid (in absence of magnetic field). The effects of the cylinder length (thickness), impedance tube terminations, and the containing fluid are discussed. The increasing of the thickness led to an increase of the TL values and a decrease in resonance frequencies. Also, the addition of liquid middle layer led to considerable increase of the TL.
基金Tarim Oilfield Corporation of China National Petroleum Corporation for providing funds
文摘Evaporation loss from the saturated soil beneath drip irrigation emitters highly influences the irrigation efficiency of drip krigation （D1]. Subsurface drip irrigation （SDI） is one good approach to curb this inefficiency, but in a new irrigation method, straight tube irrigation （STI）, the irrigation tubes do not need to be buried and thus STI is recommended to increase the irrigation efficiency under normal surface-applied DI. STI consists of only connectors and water-transference tubes that can directly transfer irrigation water from the lateral emitters in the drip line to the root zone of plants. Five-month field experiments were carried out in aeolian sand soil in the forest-belts of the Taklimakan Desert, which have poor water storage capacity, to compare the potential water saving between STI and DI. The preliminary results showed that, compared with DI, STI （1） improved the soil water content in soil depths from 40 to 100 cm under the soil surface; （2） achieved the same irrigation effects in relatively shorter irrigation durations; （3） had very little water loss due to deep seepage; and （4） formed a layer of dry sand about 10 to 30 cm thick immediately below the soil surface, which lessened evaporation loss of soil water beneath the emitters on the soil surface. This demonstrates that STI can maximize the water-saving potential of DI through the reduction of wetted soil perimeters on the soil surface. This is valuable information for water-saving engineering applications and projects with STI in arid and semiarid regions.
文摘The shock tubes with area change are used in the free piston shock tunnels,owing to its higher driver effect.For optimized operation of this kind of shock tube,a computer program for fast simulation of transient hypersonic flow is presented.The numerical modeling embodied within this code is based on a quasi-one-dimensional Lagrangian description of the gas dynamics.In this code,a mass-loss model is also applied by using Mirels′theory of shock attenuation.The simulation of particular condition for T4 free piston shock tunnel is conducted and compared with experimental measurements and numerical simulation.The results provide good estimate for shock speed and pressure obtained after shock reflection.
基金Sponsored by the National Natural Science Foundation of China(Grant Nos.11362019 and 11562018)
文摘To improve the utilization efficiency of water the laying length of porous tubes was analyzed. Considering long porous tubes the irrigation uniformity of porous tubes was studied by analyzing the deviation rate of the working head of porous tubes and through an impact analysis of the deviation ratio of flow rate based on laying length slope pressure head and perforation spacing. Results showed that the deviation ratio of the flow rate could be reduced by decreasing the length of tubes and increasing the slope. The deviation ratio of flow rate was less influenced by pressure head and perforation spacing. A best laid slope resulted in a longer laying length of the porous tubes and they were not constant.
