• Title/Summary/Keyword: 연소율

Search Result 751, Processing Time 0.027 seconds

Enhancement of hybrid rocket fuel regression rate by swirl flow configuration (스월 유동 조건에 따른 하이브리드 로켓 연료의 연소율 향상)

  • Hwang, Young-Chun;Lee, Chang-Jin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2006.11a
    • /
    • pp.232-236
    • /
    • 2006
  • 하이브리드 로켓에서 그레인 전체 부분에서 고른 연소율 향상을 이룰 수 있는 방법으로 스월 유동과 나사산 그레인을 동시에 적용하여 실험을 실시하였다. 그 결과 입구부분과 연료 후반부에 집중된 연소현상을 확인하였다. 스월 유동은 스월 유동의 종류에 상관없이 일정한 감소율을 나타낸다. 그리고 연소율 향상은 연료 벽면에서의 회전 유동 강도에 비례한다고 가정 할 수 있다. 따라서 입구부분의 집중된 연소현상을 해소하고 일정한 연소율 향상을 이룰 수 있는 스월 유동 조건에 대해 연구하였다.

  • PDF

Theoretical Analysis of the Steady Burning Rate for Homogeneous Solid Propellants with Surface Evaporation (표면 증발을 고려한 AP추진제의 정상 연소율 해석)

  • 이창진
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 1998.10a
    • /
    • pp.2-2
    • /
    • 1998
  • 고체 추진제의 연소율(burning rate)은 연소의 동적 기동을 이해할 수 있을 뿐 아니라 추진제의 성능을 판단할 수 있는 중요한 수단이기 때문에 많은 연구가 진행되어 왔다. 특히 AP계의 고체추진제 표면에서는 발열반응인 분해반응(decomposition) 이외에도 기체로 증발되는 증발되는(evaporation or sublimation)이 존재한다. 증발반응으로 인하여 연소율은 외부압력의 변화에 대하여 반응하게 되며 실험적으로 $r_{b}$= a $p^n$의 관계를 보여주고 있다. 즉, 연소율(burning rate)은 연소실 압력 P의 n승에 비례하며 여기서 n은 실험적으로 결정되는 지수이다. 그러나 압력지수 n은 일반적으로 온도와 압력의 함수이기 때문에 실험적으로 이 측정하기는 매우 어려운 일이다. 또한 QSHOD 가정을 사용하여 고체 추진제의 연소 응답함을 해석하기 위해서 추진제의 민감계수(sensitivity parameters)에 관한 관계식이 필요하며 이러한 관계식은 추진제의 정상연소율에 관한 관계식으로부터 얻을 수 있다.다.

  • PDF

The increase in the regression rate of hybrid rocket fuel by swirl flow and helical grain configuration (스월 유동과 나선형 그레인에 의한 하이브리드 로켓 연료의 연소율 향상)

  • Hwang, Yeong-Chun
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.34 no.4
    • /
    • pp.63-69
    • /
    • 2006
  • Experimental tests have been done with swirl injector and helical grain configuration to increase the regression rate of hybrid rocket solid fuel. Two types of injector were designed to evaluate the swirl effect of oxidizer stream on the increase in the regression rate. Results showed Type II injector with swirl number of 3.61 induced the better regression rate than Type I injector. Meanwhile, fuels with two different pitch number of 6 and 100 were used to analyzes the flow characteristics on the enhancement of regression rate. Test with fuels of pitch 6 showed better increase in the regression rate than in the pitch 100 when no swirler was imposed. This is due to the generation of strong turbulences in the oxidizer stream along the pitch 6 configuration. However, the regression rate could be increased further in the fuel with pitch 100 than with pitch 6 when swirl flow was imposed by Type II injector. This result implied that the fuel with pitch 100 could take a role of sustainer of the imposed swirl by swirler II instead of turbulence generator.

Combustion Characteristics of Orifice Size of Torch in a CVCC (토치 점화 장치의 오리피스 직경에 따른 연소특성 파악)

  • Kwon, Soon-Tae;Kim, Hyeong-Sig;Choi, Chang-Hyeon;Park, Chan-Jun;Ohm, In-Young
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
    • /
    • 2010.04a
    • /
    • pp.59-63
    • /
    • 2010
  • Seven different size of orifice were applied in a constant volume combustion chamber for evaluating the effects of torch-ignition on combustion. The initial flame development and flame propagation were analyzed by the mass fraction burn and combustion enhancement rate. The combustion pressures were measured to calculate the mass fraction burn and the combustion enhancement rates. In addition, the flame propagations were visualized by the shadowgraph method for the qualitative comparison. The result showed that the combustion pressure and mass burned fraction were increased when using the torch-ignition device. The combustion enhancement rates of torch-ignition cases were improved in comparison with conventional spark ignition. Finally, the visualization results showed that the torch-ignition induced faster burn than conventional spark ignition due to the earlier transition to turbulent flame and larger flame surface, during the initial stage.

  • PDF

A Study on Combustion Characteristic of the Hybrid Combustor using Non-combustible Diaphragm (비연소성 다이아프램을 적용한 하이브리드 연소기의 연소 특성 연구)

  • Moon, Keun-Hwan;Kim, Hak-Chul;Lee, Sun-Jae;Choi, Won-Jun;Lee, Jung-Pyo;Moon, Hee-Jang;Sung, Hong-Gye;Kim, Jin-Kon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2011.04a
    • /
    • pp.258-262
    • /
    • 2011
  • The hybrid combustion experiments using non-combustible diaphragm were performed for characteristic of regression rate and combustion efficiency. Results of experiments using diaphragm were showed that the regression rate and efficiency were increased. In addition, the larger difference between fuel grain port and diaphragm port increase the regression rate and efficiency. The modified regression rate equation was proposed with the port area ratio of fuel and diaphragm.

  • PDF

Influences of B Number Effect on the Burning Rate of Solid Fuel in Single Port Hybrid Rocket (Single Port 하이브리드 로켓의 고체연료 물질전달수(B Number)를 고려한 연소특성 연구)

  • Lee, Jung-Pyo;Kim, Soo-Jong;Yoo, Woo-June;Cho, Sung-Bong;Moon, Hee-Jang;Kim, Jin-Kon
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.36 no.3
    • /
    • pp.264-270
    • /
    • 2008
  • Most of burning rate models used in hybrid combustion depend solely on oxidizer flux. But this empirical relation can not represent well the important effect of the thermo-chemical properties of solid fuel and thereby requires different value of empirical exponent and constant for each fuel considered. In this study, a new burning rate correlation was proposed using the mass transfer number(B number) which encompasses the thermochemistry effect of solid fuel and the aerodynamic effect caused by the combustion on the solid fuel surface where the effect of aerodynamic property in the mass transfer number was studied. The PMMA, PP, and PE were chosen as fuel, and gas oxygen as oxidizer. The new empirical burning rate expression depending on both the oxidizer flux and the mass transfer number was able to predict the burning rate of each fuel with just a single exponent value and constant, and it was found that the aerodynamic effect on the blowing effect did show a minor effect on the burning rate correlation.

A Theoretical Study on Burning Area of Wire-Embedded Propellant Grains (금속선 삽입 추진제 그레인 연소면적에 대한 이론적 연구)

  • 오종윤
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 1998.04a
    • /
    • pp.32-32
    • /
    • 1998
  • 고체 로켓 모타 추진제 그레인은 크게 단면 연소형 그레인(end-burning grain)과 내면 연소성 그레인(perforated grain)으로 분류할 수 있다. 단면 연소형 그레인은 부피충전율이 크고 구조적 안전성이 우수한 장점이 있으나 연소면적이 작은 단점이 있고, 내면 연소형 그레인은 연소면적이 큰 장점이 있으나 부피 충전율이 작은 단점이 있다. 따라서 단면 연소형 그레인의 장점인 높은 충전율을 유지하면서 연소면적을 증대시키는 효율적인 방법으로 열전도율이 높은 금속선을 단면 연소 그레인에 삽입시키는 방법이 있다. 높은 열전도율로 인하여 금속선을 따라 연소속도가 빨라져 연소면적이 증가하게 되는데, 금속선이 없을 때의 연소속도와의 비를 연소속도 증가 비라 한다. 이는 추진제 종류, 금속선 재질, 굵기 등에 따라 달라지고, 실험실에서 strand burner test로 구할 수 있다.

  • PDF

Enhancement of Regression Rate of Hybrid Rocket Fuel by Oxidizer Injection Condition (산화제 유입조건에 따른 하이브리드 로켓 연료의 연소율 향상)

  • Hwang Youngchun;Lee Changjin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • v.y2005m4
    • /
    • pp.66-71
    • /
    • 2005
  • In this study the regression rate of hybrid rocket fuel has been investigated by two methods. First method is to use swirl injectors for enhancement of regression rate. And second method is the modification of the helical grain deriving improvement of combustion area and generating swirl flow. Tests have been done with PMMA and gaseous oxygen. In this paper the incline angle of the helical grain was varied to find the optimal condition to obtain the max regression rate for a given operational condition.

  • PDF

Effect of droplet length on a burning constant rate of suspended droplet (액적간격이 고정액적의 연소율상수에 미치는 영향에 관한 연구)

  • Han, Jae-Seob;Kim, Seon-Jin;Kim, Yoo
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.6 no.1
    • /
    • pp.47-54
    • /
    • 2002
  • This paper presents the results of an experimental investigation on the combustion of single droplets and 1-D droplet arrays of jet A-1 fuel droplets in atmospheric pressure. Experimental results indicate that burning rate constants$({\kappa}_c)$ of jet A-1 fuel droplets were independent of initial droplet size as $0.915{mm}^2$/sec. It was acquired a general relationship expressing the variation of $d^2$ with time for droplet burning For 1-D droplet arrays $(l/d_o$=1.208{\sim}2.922)$/TEX>, the burning rate constant ${\kappa}_c$ decreased with decreasing droplet spacing $l/d_o$ and, The effect on combustion rate constant ${\kappa}_c$ was stronger to second fuel droplet than third fuel droplet with uniform droplet distance

Combustion Characteristics of Volume Variation of Torch in a CVCC (토치 점화 장치의 체적에 따른 연소특성 파악)

  • Kwon, Soon-Tae;Kim, Hyeong-Sig;Choi, Chang-Hyeon;Park, Chan-Jun;Ohm, In-Young
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
    • /
    • 2010.04a
    • /
    • pp.166-170
    • /
    • 2010
  • Six different size of torch-ignition device were applied in a constant volume combustion chamber for evaluating the effects of torch-ignition on combustion. The torch-ignition device was designed six different volumes and same orifice size. The combustion pressures were measured to calculate the mass burn fraction and combustion enhancement rate. In addition, the flame propagations were visualized by shadowgraph method for the qualitative comparison. The result showed that the combustion pressure and mass burn fraction were increased when using the torch ignition device. And the combustion duration were decreased. The combustion enhancement rates of torch-ignition cases were improved in comparison with conventional spark ignition. Finally, the visualization results showed that the torch-ignition device the torch-ignition induced faster burn than conventional spark ignition due to the earlier transition to turbulent flame and larger flame surface, during the initial stage. And the initial flame propagation was effected torch-ignition volume.

  • PDF