随着软件开发费用的日益增长和不能满足用户要求的系统数量的上升,越来越多的软件组织正转向原型建造。结果产生了一个混乱的局面:一些组织建立快而脏的(quick-and-dirty)软件——抛弃式或快速原型(throwaway or rapid prototype)——...随着软件开发费用的日益增长和不能满足用户要求的系统数量的上升,越来越多的软件组织正转向原型建造。结果产生了一个混乱的局面:一些组织建立快而脏的(quick-and-dirty)软件——抛弃式或快速原型(throwaway or rapid prototype)——试图在发现用户的真正要求后,将原型抛弃,然后在现已理解的需求的基础上建立一个生产质量高的系统。另一些组织则从一开始就通过建立演化式原型(evolutionary prototype),每过一段时间就对原型进行完善,来建立高质量的系统。展开更多
The gas torque in a twin-rotor piston engine(TRPE) was modeled using adiabatic approximation with instantaneous combustion. The first prototype of TRPE was manufactured. This prototype is intended for high power densi...The gas torque in a twin-rotor piston engine(TRPE) was modeled using adiabatic approximation with instantaneous combustion. The first prototype of TRPE was manufactured. This prototype is intended for high power density engines and can produce 36 power strokes per shaft revolution. Compared with the conventional engines, the vector sum of combustion gas forces acting on each rotor piston in TRPE is a pure torque, and the combustion gas rotates the rotors while compresses the gas in the compression chamber at the same time. Mathematical modeling of gas force transmission was built. Expression for gas torque on each rotor was derived. Different variation patterns of the volume change of working chamber were introduced. The analytical and numerical results is presented to demonstrate the main characteristics of gas torque. The results show that the value of gas torque in TRPE falls to be less than zero before the combustion phase is finished; the time for one stroke is 30° in terms of the rotating angle of the output shaft; gas torque in one complete revolution of the output shaft has a period which is equal to 60° and it is necessary to put off the moment when gas torque becomes zero in order to export the maximum energy.展开更多
文摘随着软件开发费用的日益增长和不能满足用户要求的系统数量的上升,越来越多的软件组织正转向原型建造。结果产生了一个混乱的局面:一些组织建立快而脏的(quick-and-dirty)软件——抛弃式或快速原型(throwaway or rapid prototype)——试图在发现用户的真正要求后,将原型抛弃,然后在现已理解的需求的基础上建立一个生产质量高的系统。另一些组织则从一开始就通过建立演化式原型(evolutionary prototype),每过一段时间就对原型进行完善,来建立高质量的系统。
基金Project(51175500)supported by the National Natural Science Foundation of China
文摘The gas torque in a twin-rotor piston engine(TRPE) was modeled using adiabatic approximation with instantaneous combustion. The first prototype of TRPE was manufactured. This prototype is intended for high power density engines and can produce 36 power strokes per shaft revolution. Compared with the conventional engines, the vector sum of combustion gas forces acting on each rotor piston in TRPE is a pure torque, and the combustion gas rotates the rotors while compresses the gas in the compression chamber at the same time. Mathematical modeling of gas force transmission was built. Expression for gas torque on each rotor was derived. Different variation patterns of the volume change of working chamber were introduced. The analytical and numerical results is presented to demonstrate the main characteristics of gas torque. The results show that the value of gas torque in TRPE falls to be less than zero before the combustion phase is finished; the time for one stroke is 30° in terms of the rotating angle of the output shaft; gas torque in one complete revolution of the output shaft has a period which is equal to 60° and it is necessary to put off the moment when gas torque becomes zero in order to export the maximum energy.
