• Title/Summary/Keyword: Ramp Response

Search Result 55, Processing Time 0.019 seconds

Optimal Supersonic Diffuser Design of Integrated Rocket Ramjet Engine (IRR형 Ramjet Intake 초음속 확산부 형상 최적설계)

  • 민병영;이재우;변영환
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.6 no.2
    • /
    • pp.65-74
    • /
    • 2002
  • Optimal supersonic diffuser shape of integrated rocket ramjet engine was derived which maximizes the total pressure recovery. Mass flux is considered as a design constraint and the second oblique shock angle of the external ramp, the cowl-lip angle and the throat area are selected as design variables. Refined response surface method through design space transformation technique was developed and employed, and high confidence level of the regression model could be obtained. Genetic algorithm was implemented for both system optimizer and subspace regression model optimization. Virtual nozzle was located at the end of throat to adjust the back pressure. With only 20 aerodynamic analyses, optimal supersonic diffuser shape which has 14% improved total pressure recovery characteristics was successfully designed.

Validation of the fuel rod performance analysis code FRIPAC

  • Deng, Yong-Jun;Wei, Jun;Wang, Yang;Zhang, Bin
    • Nuclear Engineering and Technology
    • /
    • v.51 no.6
    • /
    • pp.1596-1609
    • /
    • 2019
  • The fuel rod performance has great importance for the safety and economy of an operating reactor. The fuel rod performance analysis code, which considers the thermal-mechanical response and irradiation effects of fuel rod, is usually developed in order to predict fuel rod performance accurately. The FRIPAC (${\underline{F}}uel$ ${\underline{R}}od$ ${\underline{I}}ntegral$ ${\underline{P}}erformance$ ${\underline{A}}nalysis$ ${\underline{C}}ode$) is such a fuel rod performance analysis code that has been developed recently by China Nuclear Power Technology Research Institute Co. Ltd. The code aims at the computational simulation of the Pressurized Water Reactor fuel rod behavior for both steady-state and power ramp condition. A brief overview of FRIPAC is presented including the computational framework and the main behavioral models. Validation of the code is also presented and it focuses on the fuel rod behavior including fuel center temperature, fission gas release, rod internal pressure/internal void volume, cladding outer diameter and cladding corrosion thickness. The validation is based on experimental data from several international projects. The validation results indicate that FRIPAC is an accurate and reliable fuel rod performance analysis code because of the satisfactory comparison results between the experimental measurements and the code predictions.

The Characteristices of Step Responses of the Manabe Standard Forms and Its Application to the Controller Desegn (Manabe 표준형의 계단 응답 특성 및 제어기설계에의 응용)

  • Gang, Hwan-Il
    • The Transactions of the Korean Institute of Electrical Engineers A
    • /
    • v.48 no.5
    • /
    • pp.586-592
    • /
    • 1999
  • We investigate the characteristic of 소데 responses of the Manabe standard form which is used recently for design of the controller. We obtain some theorems and these theorems have the properties of the relationship between the roots of the polynomial and the stability indices which are used for the Manabe standard form. The Manabe standard form has the following properties: The sum of the squal to zero, the sum of the reciprocal of the squared roots is greater than zero and the parameter $\tau$ is the negative value of the sum of the reciprocal of the roots. We compare the step responses of the Manabe standard form with those of the ITAE form, the dead beat response and Bessel forms. We choose the 6th order closed loop polynomial and keep the same settling time for the four forms. Under these conditions we find that the Manabe standard form have faster 90% rising time than the Bessel and dead beat response. We see that the ITAE, bessel and dead beat responses have some overshoot, whereas the Manabe standard form has none. We also compare the Manabe form with the other three forms for the controller design using the pole assignment technique. If the open loop transfer function is a type-1 system (transfer functions having one integrator), then, for the closed loop system associated with the open loop transfer function, the steady state error of the unit ramp input is obtained in terms of the parameter $\tau$ of the Manabe standard form.

  • PDF

Computational Study on the Hemodynamics of Cardiovascular System Including Short-term Auto-regulation Functions (단기적 자율조절기능을 포함하는 심혈관계 혈류역학 모델링에 관한 수치적 연구)

  • 심은보;정찬일;최한고
    • Journal of Biomedical Engineering Research
    • /
    • v.22 no.5
    • /
    • pp.393-402
    • /
    • 2001
  • A computational model representative of cardiovascular circulation was built using 12 standard lumped compartments. Especially, both the baroreceptor reflex and the cardiopulmonary reflex control model were implemented to explain the auto-regulation of cardiovascular system. Another important aspect of this model is to utilize the impulse-response curve of the nerve system in transferring the impulse error signals to autonomous nerve system. For the verification of this model, we have computed the normal hemodynamic conditions and compared those with the clinical data. Then. hemodynamic shock of 20% hemorrhage to cardiovascular system was simulated to test the effects of the control system model. The results of these two simulations were well matched with the experimental ones. The steady state LBNP simulation was also performed. The transient changes of hemodynamic variables due to ramp increase of bias pressure of LBNP showed good agreement with the physiological experiments. Numerical solution using only the baroreflex model showed relatively a larger deviation from the experimental data. compared with the one using the control model haying both the baroreflex and the cardiopulmonary reflex systems, which shows an important role of the cardiopulmonary reflex system for the simulation of the hemodynamic behavior of the cardiovascular system .

  • PDF

Development of DC-DC Converter for Ancillary Power Supply in Hybrid Electric Vehicle (하이브리드 자동차 보조전원 공급용 DC-DC 컨버터 개발)

  • Kim, Jong-Cheol;Choi, Deok-Kwan;Park, Hae-Woo
    • Proceedings of the KIPE Conference
    • /
    • 2005.07a
    • /
    • pp.261-265
    • /
    • 2005
  • This paper describes the DC-DC Converter for Ancillary Power Supply in Hybrid Electric Vehicle. DC-DC Converter is used for charging 12V auxiliary battery supplying electric power to head ramp, audio, ECU etc in automobiles. used DC-DC Converter Topology is PS-ZVS FB(Phase Shifted Zero Voltage Switching Full-Bridge) to reduce switching loss and EMI noise induced by high frequency operating condition. And For easy compensation and stable system response characteristic, current mode control method including slope compensation is employed. Constant current / constant voltage charging control method guarantee stable electric charging of auxiliary battery. Simulation toll PSIM6.0 is used for initial circuit parameter settings and H/W debuging. Thermal problems of Switching components in DC-DC Converter is improved by using Thermo Tracer.

  • PDF