In this article, numerical investigation of the effects of different plasma actuation strengths on the film cooling flow characteristics has been conducted using large eddy simulation （LES）. For this numerical resea...In this article, numerical investigation of the effects of different plasma actuation strengths on the film cooling flow characteristics has been conducted using large eddy simulation （LES）. For this numerical research, the plasma actuator is placed downstream of the trailing edge of the film cooling hole and a phenomenological model is employed to provide the electric field generated by it, resulting in the body forces. Our results show that as the plasma actuation strength grows larger, under the downward effect of the plasma actuation, the jet trajectory near the cooling hole stays closer to the wall and the recirculation region observably reduces in size. Meanwhile, the momentum injection effect of the plasma actuation also actively alters the distributions of the velocity components downstream of the cooling hole. Consequently, the influence of the plasma actuation strength on the Reynolds stress downstream of the cooling hole is remarkable. Furthermore, the plasma actuation weakens the strength of the kidney shaped vortex and prevents the jet from lifting off the wall. Therefore, with the increase of the strength of the plasma actuation, the coolant core stays closer to the wall and tends to split into two distinct regions. So the centerline film cooling efficiency is enhanced, and it is increased by 55% at most when the plasma actuation strength is 10.展开更多
In order to avoid serious distortion and cracking that may occur with nitrided parts while quenching and tempering, a novel kind of air cooling bainite nitriding steel consisting of Cr, Mo, Mn and Si was developed. Af...In order to avoid serious distortion and cracking that may occur with nitrided parts while quenching and tempering, a novel kind of air cooling bainite nitriding steel consisting of Cr, Mo, Mn and Si was developed. After normalized and high temperature tempered, the tested steel has satisfactory strength, toughness and microstructure as well as good nitriding properties.展开更多
In this paper,we use gambit and fluent to study the time needed and the temperature distribution of the plasma in the three frozen methods of air-cooled,plate-contact and alcohol-immersion quick freezing,this numerica...In this paper,we use gambit and fluent to study the time needed and the temperature distribution of the plasma in the three frozen methods of air-cooled,plate-contact and alcohol-immersion quick freezing,this numerical simulation was used to solve the limitation of the equipment in the actual experiment,so as to guide the experimental work.展开更多
A new method for preparing supported metal oxide catalyst has been studied by cool plasma technique and TiO 2/ γ Al 2O 3 catalyst has been prepared with ECR microwave plasma device. The activity of the catalyst was a...A new method for preparing supported metal oxide catalyst has been studied by cool plasma technique and TiO 2/ γ Al 2O 3 catalyst has been prepared with ECR microwave plasma device. The activity of the catalyst was appraised by dehydrogenative coupling of methane on pulsed discharge plasma catalysis device. The experimental results showed that the performance of the catalyst obviously is better than that of the same catalyst prepared by conventional method. In addition, the effect of plasma parameters on the catalytic performance was also studied, and the results indicated that it is a method for catalyst preparation with brilliant prospects.展开更多
文摘In this article, numerical investigation of the effects of different plasma actuation strengths on the film cooling flow characteristics has been conducted using large eddy simulation （LES）. For this numerical research, the plasma actuator is placed downstream of the trailing edge of the film cooling hole and a phenomenological model is employed to provide the electric field generated by it, resulting in the body forces. Our results show that as the plasma actuation strength grows larger, under the downward effect of the plasma actuation, the jet trajectory near the cooling hole stays closer to the wall and the recirculation region observably reduces in size. Meanwhile, the momentum injection effect of the plasma actuation also actively alters the distributions of the velocity components downstream of the cooling hole. Consequently, the influence of the plasma actuation strength on the Reynolds stress downstream of the cooling hole is remarkable. Furthermore, the plasma actuation weakens the strength of the kidney shaped vortex and prevents the jet from lifting off the wall. Therefore, with the increase of the strength of the plasma actuation, the coolant core stays closer to the wall and tends to split into two distinct regions. So the centerline film cooling efficiency is enhanced, and it is increased by 55% at most when the plasma actuation strength is 10.
文摘In order to avoid serious distortion and cracking that may occur with nitrided parts while quenching and tempering, a novel kind of air cooling bainite nitriding steel consisting of Cr, Mo, Mn and Si was developed. After normalized and high temperature tempered, the tested steel has satisfactory strength, toughness and microstructure as well as good nitriding properties.
文摘In this paper,we use gambit and fluent to study the time needed and the temperature distribution of the plasma in the three frozen methods of air-cooled,plate-contact and alcohol-immersion quick freezing,this numerical simulation was used to solve the limitation of the equipment in the actual experiment,so as to guide the experimental work.
文摘A new method for preparing supported metal oxide catalyst has been studied by cool plasma technique and TiO 2/ γ Al 2O 3 catalyst has been prepared with ECR microwave plasma device. The activity of the catalyst was appraised by dehydrogenative coupling of methane on pulsed discharge plasma catalysis device. The experimental results showed that the performance of the catalyst obviously is better than that of the same catalyst prepared by conventional method. In addition, the effect of plasma parameters on the catalytic performance was also studied, and the results indicated that it is a method for catalyst preparation with brilliant prospects.
