• Title/Summary/Keyword: Combustion velocity

Search Result 894, Processing Time 0.21 seconds

Performance Prediction of Rocket Engine Combustion and Estimation of Experimental Results (로켓 엔진의 연소 성능 예측 및 시험)

  • Park, Jeong;Kim, Yong-Wook;Kim, Young-Han;Chung, Yong-Gahp;Cho, Nam-Kyung;Oh, Seung-Hyub
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.24 no.5
    • /
    • pp.718-724
    • /
    • 2000
  • A model for depicting the rocket engine combustion process is presented and several experiments near a design point are provided with a FOOF type of unlike impinging injector for a propellant combination of Jet A-1 fuel and liquid-oxygen. The model is based on the assumption that the vaporization is the rate-controlling combustion process. The effects of initial drop size and initial drop velocity are systematically shown and discussed. It is seen that in the midst of considered parameters the change of initial drop size is more sensitive to the performance. The proposed model describes qualitative trends of combustion process well despite of its simplicity.

A Study On The Gas-Flow In the Four-Stroke Engine At Compression Stroke (사행정기관의 압축행정시의 가스유동에 관한 연구)

  • 이기명
    • Magazine of the Korean Society of Agricultural Engineers
    • /
    • v.17 no.4
    • /
    • pp.3970-3979
    • /
    • 1975
  • On account of the development of the high speed internal combustion engines, several methods for increasing burning velocity has been investigated lately. Installation of a squash area on a cylinder head is one of the simple and practical method to induce the strong tubulant flow of air-fuel mixtureinto a combustion chamber. In this study, a four-stroke engine used for agricultural purpose was tested as an experimental model. A mathematical model of the squash velocity was derived, and also, several characteristics of the squash phenomena during the motoring of the engine used as a modelwere investigated. The results obtained were as follows: (1) Mathematical model of squash velocity was established and cheked (2) Squaash velocity and engine speed were found to be proportional to the squash area while they were inversely proportional to the squash width. (3) Squash velocity and crank angle at which the squash velocity become its peak were influenced by the magnitude of squash clearance: increase of squash clearance made squash velocity reduced acd made the peak of the squash velocity for from the top dead center and (4) When the squash area is divided in small areas baving unit width along the squash section, squash velocity at each unit width was proportional to the magnitude of the squash distance covered by the unit width.

  • PDF

Measurement of Air Motion in a Diesel Engine Combustion Chamber using Hot Wire Anemometer (열선유속계에 의한 디이젤기관 연소실내의 공기유동 측정)

  • U, Dae-Seong;Go, Dae-Gwon;An, Su-Gil
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.23 no.2
    • /
    • pp.86-94
    • /
    • 1987
  • In order to examine the flow motion in a combustion chamber of a motored diesel engine, the variation of instantaneous are velocity at a fixed point in combustion chamber was measured by the constant temperature hot wire anemometer, varing engine speed, shroud shape and shroud position. The results are summerized as follows: 1. The variation of air velocity in a combustion chamber is closely related with the valve timing and piston velocity. 2. The air velocity in the cylinder at suction stroke is being increased and maximized at 60$^{\circ}$ ABDC in compression stroke and then decreased at the e.v.o. in expansion stroke. 3. The mean velocity using shroud valve was less than no shroud valve. However the turbulent intensity using shroud valve was larger than no shroud valve. 4. The turbulent intensity with 90$^{\circ}$shroud valve was larger than that of 120$^{\circ}$shroud valve, and 90$^{\circ}$shroud valve at 180$^{\circ}$shroud position had the largest turbulent intensity.

  • PDF

Measurement of Air Motion in a Diesel Engine Combustion Chamber using Hot Wire Anemometer (열선유속계에 의한 디이젤기관 연소실내의 공기유동 측정)

  • Dae-Sung Woo;Dae-Kwon Ko;Soo-Kil Ahn
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.23 no.2
    • /
    • pp.40-40
    • /
    • 1987
  • In order to examine the flow motion in a combustion chamber of a motored diesel engine, the variation of instantaneous are velocity at a fixed point in combustion chamber was measured by the constant temperature hot wire anemometer, varing engine speed, shroud shape and shroud position. The results are summerized as follows: 1. The variation of air velocity in a combustion chamber is closely related with the valve timing and piston velocity. 2. The air velocity in the cylinder at suction stroke is being increased and maximized at 60° ABDC in compression stroke and then decreased at the e.v.o. in expansion stroke. 3. The mean velocity using shroud valve was less than no shroud valve. However the turbulent intensity using shroud valve was larger than no shroud valve. 4. The turbulent intensity with 90°shroud valve was larger than that of 120°shroud valve, and 90°shroud valve at 180°shroud position had the largest turbulent intensity.

An Experimental Study on the Flame Stability of Natural Gas/Air Mixture on the Metal Mesh (금속매쉬에서 천연가스/공기 표면연소의 화염안정성에 관한 실험적 연구)

  • You, Hyun-Seok;Lee, Hyun-Chan;Lee, Joong-Sung
    • Proceedings of the KSME Conference
    • /
    • 2001.06d
    • /
    • pp.49-53
    • /
    • 2001
  • A conventional flame type gas combustion major portion of heat is transferred to the body by convection due to small radiant ability of the gas flame. Increasing the radiation component of heat flux in the combustion zone allows to augment the efficiency of gas utilization. Such effect can be reached by using radiative gas burner applied to metal mesh combustion. Basically the gas radiant burner consists of metallic mesh of high heat resisting steels. In terms of this regards, we have made the burner consisted of metal mesh and measured the radiative flame stability of natural gas/air mixture on the metal mesh burner. The pressure loss through the metal mesh is defined by pressure-velocity slope. The more increased the pressure-velocity slope of the metal mesh is, the wider the stable zone of radiave flame on the metal mesh burner is. And the augmentation of mixture flowrate through the metal mesh make narrow the permissible range of equivalence ratio.

  • PDF

Effect of MgO Diluents in Combustion Synthesis of TiB2 Nano Particles (TiB2 나노 입자의 연소합성 시 MgO 희석제가 미치는 영향)

  • Lee, Byung-Ki;Lee, Jong-Moo;Park, Je-Hyeong;Kang, Eul-Son;Baek, Seung-Soo;Kim, Do-Kyung
    • Journal of the Korean Ceramic Society
    • /
    • v.42 no.9 s.280
    • /
    • pp.607-612
    • /
    • 2005
  • The effect of MgO diluents in combustion synthesis of $TiB_2$ nano particles was investigated. The reaction $TiO_2\;+\;B_2O_3\;+\;xMg\;{\rightarrow}\;TiB_2\;+\;5MgO$ was used to synthesize $TiB_2$ nano particles. The combustion velocity was measured to examine the relation between the reaction temperature and the morphologies of particles. The diluent MgO did not react with the reactants and played a role to decrease combustion temperature. As the MgO diluents contents increased, the particles with the smaller size and the narrower size distribution were synthesized. At the condition of 6 mole of MgO, the combustion wave velocity was about 5 cm/see and the synthesized particles showed the size of 60 nm with narrow size distribution.

Study on the Thermodynamic Properties and Combustion Information of Natural Gases from Various Producing Districts (산지별 천연가스들의 열 물성치 및 연소 정보 검토)

  • Lee, Chang-Eon;Hyun, Seung-Ho;Hwang, Cheol-Hong;Lee, Sung-Min;Ha, Young-Cheol;Lee, Kang-Jin
    • Journal of the Korean Society of Combustion
    • /
    • v.12 no.1
    • /
    • pp.38-47
    • /
    • 2007
  • The diversification of import districts of natural gas is trying to prepare an increase in the demand and price. The interchangeability of natural gases should be examined prior to supply to gas appliances, although compositional differences among natural gases are not large. The object of this study is to investigate numerically the thermodynamic and transport properties as well as information on combustion of 6 natural gases. Comparing the properties of BOG1 with those of standard gas, the maximum differences of heating value, Wobbe index, air-fuel ratio, and specific heat are 10%, 4%, 10% and 5.54%, respectively. That is, the BOG1 is required careful application. However, all gases except for BOG1 show the similar properties with standard gas. Finally, the combustion information such as flame temperature and burning velocity are examined. These results will provide the useful information related to the interchangeability of various natural gases in practical combustion appliances.

  • PDF

Combustion Instability and Active Control in a Dump Combustor (덤프 연소기에서의 연소불안정과 능동제어에 대한 연구)

  • Ahn Kyu-Bok;Yu Kenneth;Yoon Young-Bin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2005.11a
    • /
    • pp.445-449
    • /
    • 2005
  • The mixed acoustic-convective mode combustion instability and the possibility of combustion control using a loudspeaker to these instabilities were studied. By changing inlet velocity, combustor length and equivalence ratio, the dynamic pressure signals and the flame structures were simultaneously taken. The results showed that as the combustor length increased and the inlet velocity decreased, the instability frequency decreased and the maximum power spectral densities of the dynamic pressures generally decreased. The instability frequency could be affected by an equivalence ratio over the operating conditions. From the data of close-loop control, as the loudspeaker may work out-of-phase with the natural instability, the optimum time-delay controller was confirmed to be able to reduce the vortex shedding from the mixed acoustic-convective mode combustion instability.

  • PDF

A Study on Turbulence Flow Characteristics at the Spark Plug Location in S.I. Engine (가솔린기관의 점화플러그 위치에서 난류유동 특성에 관한 연구)

  • 정연종;조규상;김원배
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.18 no.9
    • /
    • pp.2423-2430
    • /
    • 1994
  • Several factors of the efficient combustion process are shape of combustion chamber, position of spark plug, turbulence flow and so on. the shape of combustion chamber and position of spark plug are constrained to geometrically, and then it could not make a change the shape easily. But the turlence flow in combustion chamber have a great influence on combustion phenomena, and which is much easier to control relatively. And since characteristics of turbulence flow would be very important to the stability of combustion and performances, This study is also essential to future engine-low emission and lean burn engine. This paper shows that the visualization of the turbulence flow of single cylinder engine by using 2way, $45^{\circ}$ inclined and 2 channel hot wire probe through the park plug hole. We also study the characteristics of turbulence flow by means of ensemble averaged mean velocity, turvulence intensity and integral length scale.

A Study on Combustion Characteristics in Hybrid Rocket using Liquefying Diaphragm (용융성 다이아프램을 이용한 하이브리드 로켓의 연소 특성 연구)

  • Kim, Hak-Chul;Kim, Soo-Jong;Jeon, Doo-Sung;Woo, Kyoung-Jin;Lee, Jung-Pyo;Moon, Hee-Jang;Sung, Hong-Gye;Kim, Jin-Kon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2010.11a
    • /
    • pp.474-478
    • /
    • 2010
  • Hybrid rocket combustion experiments using liquefying diaphragm made by blended liquefying fuel with 10 wt% of LDPE were performed. Results of experiments were compared to the those of pure paraffin. In case of using liquefying diaphragm, regression rate of rear fuel grain, characteristic velocity and specific impulse highly increased due to the induced turbulent intensity and heat transfer. The serious combustion instability was not observed in analysis of combustion instability. These results can imply that the liquefying diaphragm is efficient to improve low combustion efficiency in hybrid rocket using liquefying fuel.

  • PDF