Recently, the Cartesian grid method was used on simulations of fluid flow around the complex geometry problems. In this paper, the Cartesian grid method with cut cells are used to simulate incompressible viscous flows around moving objects. In this study, the small cut cells are merged with neighboring cells. The code was developed based on Fractional Step Method on Finite Volume Method. In time integrate, the second order explicit Adams-Bashforth method was used for the convective terms and second order implicit Crank-Nicholson method was used for the diffusive terms. Some moving boundary problem are simulated using the presented code and compared with other previous numerical and experimental results.

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The horizontal stratified two-phase flow in the rectangular pipe whose width is smaller than the height is simulated by the one-component two-phase lattice Boltzmann method. The interfacial growth between two phases is measured for three cases with the different pipe width and the measured dimensionless number chasacterizing the two-phase flow is compared with the flow regime map proposed by Taitel and Dukler. It is found that the boundary separating the interfacial growth from the non-growth which is obtained by the simulations is larger than that in the flow regime map when the pipe width is narrower.

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An experimental investigation was made of the pulsating turbulent flow in conically divergent tubes with divergence angles of 12, 16 and 24°. The experiments were carried out under the conditions of the Womersley numbers of α=10-40, the mean Reynolds numbers of Re_ta=15000-30000 and the oscillatory Reynolds number of Re_os=10000 (the flow rate ratios of η=0.33-0.67). Time-dependent wall static pressure and axial velocity were measured at several longitudinal stations and the distributions were illustrated for representative phases within one cycle. The experimental results of the rise between the pressure at the inlet and the outlet of the divergent tube almost agree with the approximate results, which are derived under the assumption of a quasi-steady flow. The profiles of the phase-averaged velocity and the turbulence intensity in the cross section are quite different from those of a steady flow and also they show complex changes along the tube axis in each of the accelerative and decelerative phases.

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In a stronger wall jet managed by a streamwise vortex, effect of periodic perturbation on the interaction and evolution processes has been investigated in the equations derived from phase averaging and triple decomposition. Transverse and spanwise locations of vortex center have time variations associated with variation in strength of streamwise vortex. Normal Reynolds stress difference (V²-W²) and shear stress VW generated by periodic perturbation reduce decay rate of maximum vorticity and accelerate growth rate of spanwise vortex radius in terms of production terms in transport equation for streamwise vorticity. Prediction of Reynolds shear stress component VW by taking account of time variation of both vortex center and strength successfully explains experimental data of conventional time average stress of vw.

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Active mixing control of gaseous coaxial jets is achieved using magnetic flap actuators arranged on the inner periphery of the outer annular nozzle. The spatio-temporal velocity fields and scalar mixing are studied through a particle image velocimeter and a laser-induced fluorescence method. Flap motion forces the outer shear layer to roll up into large-scale ring vortices. When the momenum flux of the annular jet is much larger than that of the central jet, the inner shear layer also rolls up into large-scale vortices, which pinch off the central jet significantly. Near-field mixing process is dominated by the ring vortices, while streamwise vortices generated through the breakdown of the ring vortices are responsible for the mixing at the downstream. The near-field mixing is characterized by the length scale of ring vortices and the Strouhal number, which is defined as the ratio between the dimension and shedding interval of the vortices. When the Strouhal number is unity and the vortex size is comparable to the nozzle radius, the mixing is enhanced most significantly since the near-field is most densely populated with the large-scale vortices.

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A stabilization time of a wake structure behind hypersonic vehicles is very important in experiments on the flow structure by using pulsed facilities of high enthalpy or of high Mach number. However, observations themselves of such wake structure have been very difficult, and therefore, the experimental discussion about the stabilization time itself has also been very difficult. In this study the stabilization time of the wake structure was formulated by using the dimensional analysis and the present experimental results. The experiment was carried out by observing separation points and free shear layers just after three re-entry capsule models. To visualize the wake structure, one of techniques called the electrical discharge method was utilized. From these investigations it was found that the stablization time of the wake structure was related to the Reynolds number, the model scale, and the freestream velocity. A hypersonic gun tunnel of Mach 10 was used in this experiment.

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Aerotrain is a high speed ground transportation system using natural energy resources. It has vertical side wings at each tip of main wings arranged in tandem to regulate automatically its lateral position in a guide way by the Wing-in-Ground effect between the side wings and side walls. According to the data obtained from the wind tunnel experiment, the interaction of main wing and side wing was higher in the ground effect than in free stream condition. The present work tried to raise the aerodynamic efficiency by using attached fillet in the sharp corner between the side wing and main wing, we can considerably improve the aerodynamic characteristics, that is, over all lift to drag ratio of the model. The results show that the optimum conditions of lift to drag ratio depends on the elimination of separation area by means of the shape and size of the fillet.

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An improved cavitation model and treatment has been developed for the prediction of the flow field resulting from an attached cavitation region. The cavitation model is implemented in a viscous calculation basing on a Reynolds Averaged Navier-Stokes (RANS) equations solver with the effect of turbulence taken into account. A priori knowledge of the wall detachment point and bubble length is not required but naturally a part of the solution by this cavitation model. The liquid/vapor interface is tracked and obtained by an iteration procedure between the flow field computation and interface updating. An improved interface updating technique has been proposed to speed up and stabilize the iteration process. A series of computation has been carried out for internal and external flows of different configurations. The code and the cavitation model have been well validated by comparison of the computations against the experimental data available. The computations also demonstrate the feasibility of the improved cavitation model and treatment to flows in complicated configurations.

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Various types of cavitation instabilities are considered to occur when steady cavity length becomes longer than 65% of blade spacing in high-speed turbomachinery, such as turbopumps for rocket engine. If we estimate the steady cavitation, the inception of unsteady cavitation could be predicted. Then, we propose an analytical method for the prediction of steady cavitation in turbomachinery under the assumption that stream surface is rotationally symmetric. The analysis on stream surface is performed by a singurality method based on closed cavity model and is combined with the analysis on meridian plane through the circumferentially averaged velocity. The present method is applied for a flat-helical inducer and three-dimensional effects on cavitation are discussed in comparison with the results of the analysis of two-dimensional flow.

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The effects of inlet casing geometries on unsteady cavitation were investigated with a 3-bladed inducer. Through the experiments with various types of casings, the unsteady cavitation occurrence range in cavitation number was examined for various flow rates. It was found that the onset point of rotating cavitation moves to lower cavitation number when the tip clearance was increased. The size and location of casing enlargement affected the occurrence of cavitation instabilities significantly. Backflow at inducer inlet and tip cavity were also investigated to obtain the information to understand the mechanism of suppression of unsteady cavitation by changing the geometry of the casing.

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In the flow around a circular cylinder, the sudden decrease in the drag force occurs at a high Reynolds number, but the same phenomenon occurs at a lower Reynolds number in the case where there exist grooves or roughness on the circular cylinder surface. In this paper, in order to make clear the flow characteristics around a circular cylinder with triangular grooves, drag coefficient, pressure distribution and Strouhal number were measured. Moreover the flow was analyzed by applying the RNG k-ε turbulent model and the surface flow pattern was investigated using oil-film technique. Consequently, it is made clear that the reattachment point changes position in each groove and the drag coefficient of a circular cylinder with triangular grooves decreases compared with a circular cylinder with arc grooves.

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For the first step to clarify the validity of the dissipative particle dynamics method, which is a mesoscopic simulation technique, we have derived the expression for the transport coefficient such as the viscosity, from the equation of motion of the dissipative particles. In the concrete, we have first shown the Fokker-Planck equation in phae space, and the macroscopic conservation equations such as the equation of continuity and the equation of momentum conservation. Then, we have derived the basic equations of the single-particle and pair distribution functions using the Fokker-Planck equation. The solutions of these distribution functions have approximately been solved by the mehod of perturbation method under the assumption of the molecular chaos.Finally, the expression of the viscosity due to the momentum and dissipative forces has been obtained using the approximate solutions of the distributions.

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This paper presents a new method for measuring the interfacial displacement of a liquid film in microchannels using a laser focus displacement meter (LFD).The purpose of the study is to clarify the effectiveness of the new method for obtaining detailed information concerning interfacial displacement, especially in the case of a thin liquid film, in micro- and mini-channels. To prevent the tube wall signal from disturbing that of the gas-liquid interface, a fluorocarbon tube with water box was used ; the refraction index of this device is same as that for water. With this method, accurate instantaneous measurements of interfacial displacement of the liquid film were achieved. The error caused by refraction of the laser beam passing through the acrylic water box and fluorocarbon tube was estimated analytically and experimentally. The formulated analytical equation can estimate the real interface displacement using measured displacement in a fluorocarbon tube of 25μm to 2.0 mm I.D. A preliminary test using fluorocarbon tubes of 1 and 2 mm I.D. showed that the corrected interface displacement calculated by the equation agreed with real displacement within a 1% margin of error. It was also confirmed that the LFD in the system could measure a liquid film of 0.25 μm at the thinnest. We made simultaneous measurements of the interface in fluorocarbon tubes of 0.5 and 1 mm I.D. using the LFD and a high-speed video camera with a microscope. These showed that the LFD could measure the interface of a liquid film with high spatial and temporal resolution during annular, slug, and piston flow regimes. The data also clarified the existence of a thin liquid film less than 1 pm in thickness in slug and annular flow regions.

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Spectroscopic measurements were made of a shock layer generated by a flat-head body in high-enthalpy air and nitrogen plasma flows of NAL 750 kW arc-jet wind tunnel. In the wavelength region of 350 nm to 450 nm, N₂⁺ 1- band was predominant in the nitrogen jets and the N₂⁺1-and CN violet bands in the air jets. These bands were analyzed in detail by using synthetic spectra calculated theoretically. Temperature determination of the shock layer was tried by applying a spectral matching method to these band systems. In case of the nitrogen plasma jet, axial temperature distribution across the shock layer was measured and compared with the flow calculation based upon the modified fully-merged shock layer theory. It was found that the rotational temperature in the shock layer for both the arc jets was about 7000 K, and the tempeature of a free stream in the nitrogen plasma jets was much higher than that expected.

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In the secondary flow within a passage of a turbomachinery, the passage vortex generates a major part of the losses. In a series of studies, the passage vortex is closely analyzed by the numerical computations using curved ducts as fundamental models for the generation of the passage vortex. The flows in the curved ducts are examined by relating the bend of curved duct to the blade-to-blade surface of an axial flow turbine cascade and to the meridional plane of a centrifugal impeller. The cross-sections of passage of a turbomachinery have various aspect ratios. In this study, the cross-sectional aspect ratio is chosen as the major parameter affecting the loss generation cuased by the passage vortex. The computed results clarified that the decrease of the aspect ratio strengthened the passage vortex and consequently, increased the loss caused by the passage vortex.

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This paper reports on indirect cooling of high-power CPU of notebook computers using a two phase closed thermosyphon loop with Fluorinert (FC-72) as the working fluid. The experimental set-up consists of an evaporator and a condenser connected by flexible tubing. The evaporator corresponds to a high-power CPU, and the condenser represents a cooling plate located behind the display of notebook computer, The evaporator and the condenser have the outer dimensions of 50mm×50mm×20mm and 150mm×200mm×20mm, respectively. The effects of the heat input Q and the charged volume of Fluorinert liquid F on the heat transfer characteristics of the cooling system were studied experimentally. Further, the experiments using several types of evaporators to enhance the boiling in the evaporator were carried out. It has been confirmed that the back surface temperature of the evaporator with plate fin of roughness surface by blast (Type D) reduces about 18% in comparison with that of the evaporator without fin (Type A). In the case of the evaporator Type D, the temperature difference between the evaporator back surface and ambient is kept around 55 K for the highest heat input Q=30 W in the present experiments.

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An experimental study has been conducted to understand characteristics of transient heat transfer during quenching a hot cylidrical block with an impinging water jet. The experiment was done at atmospheric pressure for the following condition : an initial block temperature of 250 and300°C, a subcooling of 20-80 K, a jet velocity of 3-15 m/s, and a nozzle diameter of 2 mm. The surface temperature and heat flux are estimated by applying two-dimensional inverse solution to the measured temperatures in the block during the quench and then the flow configuration on the surface during the quench is synchronously observed with high speed video. As a result, the changes in the surface temperature and in the surface heat flux are clearly shown with movement of the wetting front. The resident time at which the wetting from starts spreading after the impingement of jet can be predicted by a proposed correlation. The fundamental character of how the surface temperature and heat flux changes with the wetting front, can be understood.

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Water cooling panels are adopted as a vessel cooling system of a High Temperature-engineering Test Reactor (HTTR) to cool the reactor core indirectly by natural convection and thermal radiation. In order to investigate heat transfer characteristics of high temperature gas in a vertical annular space between the reactor pressure vessel and the cooling panels of the HTTR, we carried out experiments and numerical analyses on natural convection heat transfer coupled with surface-to-surface thermal radiation in a vertical annular space of a double coaxial cylinder. In the present experiments, Rayleigh number based on the height of the vertical space was set to be 2.0 × 10⁷ < Ra < 5.4 × 10⁷ for helium and 1.2 × 10⁹< Ra < 3.5 × 10⁹ for nitrogen. The numerical results were in good agreement with the experimental ones regarding the temperature on the heating and cooling walls, and so on. As a result of the experiments and the numerical analyses, a heat transfer coefficient of natural convection coupled with surface-to-surface thermal radiation was obtained as functions of Rayleigh number, radius ratio, temperature and emissivities on the heating and cooling walls.

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This study is concerned with the self-control of thermal convection in porous insulating layers utilizing a shape memory screen. A numerical analysis shows that the shape memory screen, which causes the temperature dependency of flow resistance, brings about the transition from large-scale convection to local-scale convection. It is found that the shape memory screen can change the performance of the insulation by modifying the temperature distribution of the thermal convection.

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A new numerical scheme, precise time integration (PTI) method was applied to unsteady heat conduction problems. The algorithm of the PTI method and the way to create coefficient matrices and vectors for the unsteady heat conduction problems were described in detail in this paper. The comparison between the PTI and the ordinary finite difference methods showed that the PTI method's solutions for one and two-dimensional heat conduction problems were more accurate than those of ordinary methods for a wide range of mesh Fourier number f. The comparison also showed that the PTI method needed larger memory capacity and longer time for calculations than the ordinary methods did.

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To analyze the performance of the heat exchangers (HEXs) in air-conditioners within a realistic time frame, we propose a simple modeling technology that uses a reduced mesh. The pressure loss of the HEX is given by the momentum source term, and the heat-transfer performance of the HEX is approximated by using a wall function as the boundary condition. We compared analytical results of this simple analysis model with the measured results for heating conditions for different indoor systems. The air-flow rate of the simple analysis model agreed with that of the experimental results within a 1% error margin, and the heating capacity of the simple model agreed with that of the experimental result within a 2% error margin.

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This paper describes the strict derivation of the power spectrum method to evaluate effective heat transfer coefficients required to predict the surface temperature fluctuation from the measured fluid temperature. Two prediction methods of metal surface temperature fluctuation : “Improved Time Range Method” and “Frequency Range Method” were proposed using the effective heat transfer coefficient predicted by the power spectrum method and fluid temperature fluctuation data. The prediction errors of these methods were investigated using parallel impinging jet test data. It was found that the metal temperature fluctuations predicted by the two methods agreeded with the corresponding experimental data and the validity of the methods were demonstrated. Metal surface temperature fluctuation was predicted by the two methods. The predicted results appeared to be in good agreement each other and no marked difference in prediction accuracy were found between the Time Range Method and the Frequency Range Method.

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Combustion of wire insulation is important for fire safety in Space. Insulated wire has two unique features, one is sample geometry and another is existence of wire core. In this paper we investigate the effect of core materials on combustion phenomena of insulated wires. An experimental study of flame spread phenomena over polyethylene insulated wires with two different core materials, copper and nichrom, in different O₂ concentrations was performed in microgravity. The experiments were performed at the Japan Microgravity Center (JAMIC) 10 s dropshaft. Experiments were performed with different O₂ concentration and core material. The results show that the core material strongly affects the flame shape irrespective of gravity level. The flame spread rate is also strongly affected by the core material. Under normal gravity, the flame spread rate with copper cores is faster than that with nichrom cores in any of the tested oxygen concentrations. In microgravity, the effect of the core materials on the flame spread rate changes by oxygen concentration. In 35% O₂, flame spread rate with copper wire was faster than that with nichrom core wire, as also seen in the normal gravity case. In 21% O₂, the flame spread rate with the nichrom core wire is faster than that with copper core wire. The core heat conduction analysis shows that the thermal conductivity of the core material has an important effect on the flame spread rate. The case of high flame temperatures, the core acts as a heat source and high conductivity material supplies more heat to the insulation. At low temperatures, the core becomes heat sink and high conductivity material causes heat removal from the insulation near the flame front.

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Characteristics of self-excited combustion oscillation are experimentally studied using confined premixed flames stabilized by a rearward-facing step. A new idea to suppress combustion oscillation was applied to the flames. We examined the characteristics of unsteady combustion driven by forced pulsating mixture supply that can be modulated its amplitude and frequency. The self-excited combustion oscillation having flow velocity fluctuation intensity weaker than that of the forced pulsating supply can be suppressed by the method. The effects of the forced pulsation amplitude and frequency on controlling self-excited combustion oscillations were also investigated comparing with the steady mixture supply. The unsteady combustion used in this experiment plays an important role in controlling self-excited combustion oscillations, and it also exhibits desirable performances, from a practical point of view, such as high combustion load and reduced pollutant emissions of nitric oxide.

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Unburned hydrocarbons from a direct injection stratified charge engine were greatly reduced by a large amount of hot EGR. A hydraulically controlled variable valve system was used to realize the hot EGR. Almost all the amount of required EGR gas for the NO_x reduction was supplied directly from the previous cycle through the exhaust or inlet valves. Two kinds of recirculation were examined in this test. The first was the recirculation through the exhaust valves, which opened additionally during the suction stroke. Another was the recirculation through the inlet valves. The exhaust gas was pushed back to the port during the exhaust stroke through the additionally opened inlet valves and re-induced in the next cycle. Although both methods have the same ability to reduce HC emissions, required EGR was less in the latter method.

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An experimental study has been carried out to reveal the statistical characteristics of the onset of micro-explosion of an emulsion droplet evaporating and burning on a hot surface. The oil-in-water emulsion consisting of base fuel and water doped with small amount of surfactant is tested after degasification. Detail measurements of the waiting time for the onset of micro-explosion are made for various water contents and surface temperatures. Photographic observation and temperature measurements are made to understand the transport processes of liquid phases inside the droplet and the rate of micro-explosion. The results show that the agglomeration and separation of the water and the base fuel layers occurs prior to the micro-explosion. It is also confirmed that the distribution function of the waiting time is correlated with the Weibull distribution of the wear-out type. An empirical formula is proposed for the rate of micro-explosion as a function of droplet temperature and volume of water layer.

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An experimental study was performed to clarify the operation condition on natural gas fueled homogeneous charge compression ignition engine. Using a single cylinder engine, operation range, engine performance and exhaust emissions were measured under various intake air temperature, compression ratio and equivalence ratio. Under the high intake air temperature, combustion efficiency is high, but under lower temperature, engine was operated in narrow A/F range. The use of high compression ratio, engine was operated at lower intake air temperature. To keep combustion efficiency over 80% and NO_x emission under 10 ppm, maximum in-cylinder temperature should be controlled within the narrow range between 1 500 K and 1 800 K. Natural gas auto-ignited over 1 000 K and the effect of A/F was low. Auto ignition temperature was decreased according to the decline of intake air temperature.

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Entablishment of recycling energy system utilizing biomass as the storage of solar energy must be expected for the fundamental solution of global problems such as petroleum exhaustion and climate change. Final goal of this study is to realize a compression ignition and spray combustion engine system with higher efficiency and controllability using biomass-based alcohol fuels such as Methanol and Ethanol. As the first step of this research, in order to make clear the ignition and combustion characteristics of alcohol fuels, five kinds of alcohols and gas oil were tested in a small sized DI Diesel engine with glow-assisted ignition system. The test results show that difficulties of controlled ignition of alcohols are due to difficulties of mixture formation of suitable mixing ratio and attainment of required temperature of mixture for spontaneous ignition at the same time and place in a spray. Combustion rate and duration after ignition are affected with average mixing ratio of fuel sprays at the ignition timing.

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The drive to reduce greenhouse emissions and the dependence on fossil fuels has produced considerable interest in the use of biomass energy. Gasification of biomass is given attention since the process is simple and clean. It is necessary for optimum designing of biomass gasifier to understand the behavior of pyrolysis and to couple pyrolysis reaction rates of biomass with CFD (Computational Fluid Dynamics). The purpose of this study is to know the behavior of biomass pyrolysis and to fomulate chemical reaction rates of pyrolysis products under the high heating rate (5K/s). The major component of wood, cellulose, was pyrolyzed at temperature raging from 250 to 700°C. Cellulose was pyrolyzed at temperature raging from 250 to 700°C. Also, biomass pyrolysis was applied to a first-order Arrhenius type kinetic model. It was found that calculated value could reasonably represent the yields of gas, tar, water and main gas spices (CO and CO₂). Therefore we could propose reaction rates of primary reaction, which predicted quantity of biomass pyrolysis products.

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Spark ignition characteristics of flanged spark plugs have been studied experimentally. Experiments were performed using a constant volume combustion chamber and a natural gas engine. Flanged spark plugs were made by remolding spark plugs on the market. The minimum ignition energy was employed to evaluate the ignition characteristics of the flanged spark plugs. It was found that the flanged spark plug reduces the minimum ignition energy. It was observed by schlieren photography that the shock wave was reflected by the flanges concentrated on a flame kernel. This fact suggests that the adiabatic compression due to the shock concentration reduces the minimum ignition energy. There is little effect of the flange on the flame speed, although it is well known that the existence of flanges prevents the initial growth of the flame kernel. It was found that, in actual engine test, the ignition probability is increased and the lean limit is extended.

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Hydrogen Energy is expected to be one of the keys to sustainable development. But this expectation comes from the idea focusing only on the particular phase of interest, such as production or use phase of hydrogen energy. The sustainability of the hydrogen energy will be clear by considering the Life-Cycle of the hydrogen energy system. In the present study, using the method of the Life-Cycle Assessment, the hydrogen energy system was analyzed considering the construction of infrastructures. The assessment aspects are Energy, CO₂, Cost and Land-Use. The hydrogen energy was also examined the adaptability to the vehicle fuel. The hydrogen energy which improves environmental impacts and costs in the acceptable range was selected. As a result, hydrogen energy for the vehicle fuel has to be produced by natural-gas reforming. And if the carbon tax is introduced, water electrolysis using the nuclear power is also possible.

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Characteristics of the flow inside an engine cylinder model have been evaluated by a particle image velocimetry (PIV) and a laser Doppler anemometer (LDA). Verifications of the results by Partial Cells in Cartesian coordinate method numerical simulation have been also made by the experiment results. The model engine head that has two intake valves and transparent cylinder are used in the steady state flow condition. The tests are conducted by single- and dual- valve open condition with 8 mm valve lift in-1470 Pa suction gauge pressure. The comparisons between the PIV and the LDA experiments show almost the same tendencies for mean velocities and turbulence intensities in the whole experimental regien qualitatively and also quantitatively. The differences in the valve open condition are clearly observed in the integral length and time scales that are estimated from the PIV and LDA data respectively. It is shown that the PIV results are useful for verification of numerical results, which agree reasonably with those of experiments.

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In order to measure the fuel jet concentration quantitatively, a technique combining methods of fluorescence with absorbance was developed. LIF method can estimate the spatial fuel distribution qualitatively, but quantitative measurement is difficult. Meanwhile, absorbance method can quantitatively obtain the integrated concentration on the light-path. Thereby, a combination of this technique and laser-beam-scanning technique enables us to measure the quasi 2-D fuel concentration quantitatively. In this study, this measurement method was applied to fuel jet fields in a constant volume bomb. As a result, quasi 2-D measurements of gas concentration were successfully attained by adopting some compensation techniques.

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Experiments were carried out on the spontaneous ignition of single fuel droplets in lean premixtures of fuel vapor and air. The n-dodecane droplet was rapidly inserted into high temperature environments and the ignition delay time was obtained from the measurement of OH emissions. Methane and propane were employed as the fuel of premixtures. The waiting time between the introduction of premixture into the hot furnace and the start of experiment of droplet ignition is defined as the residence time. The calculation of chemical reaction of fuel vapor-air mixtures in high temperature during the residence time was also conducted in order to explore the time history of chemical species concentration. In the case of short residence time where the reaction of premixtures does not proceed so much, the ignition delay time is almost the same as that in the air environment, which indicates that the existence of fuel vapor in ambient environments has little effect on the spontaneous ignition behavior. The ignition delay time becomes larger than that in air in the long time residence time, which is due to the decrease in the oxygen concentration in premixtures.

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A zero-dimensional engine cycle simulation has been developed by implementing chemical kinetics as the auto-ignition model into the two-zone combustion chamber model. A mixed chemical reaction mechanism of the primary reference fuels is used. Experimental data have been carefully investigated to obtain correlation between calculated auto-ignition of the end-gas and actual knock intensity. The result shows that a combination of time of auto-ignition occurrence and heat release by auto-ignition can explain knock intensity. This correlation has been applied to the simulation so that it can predict knock occurrence including knock intensity. A number of calculations have been done under various engine parameters including compression ratio, intake temperature, octane rating and equivalence ratio. The results show that fair levels of agreements are obtained between calculated trace knock spark advance sensitivity and experimental trends.

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