A hot-flow axisymmetric Air Augmented Rocket (AAR) test apparatus was constructed to test various mixing duct configurations at static conditions. Primary flow for the AAR was provided through a liquid methanol-gaseous oxygen bipropellant rocket. Experimental thrust measurements were recorded and propellant mass flow rates and chamber conditions were calculated using an iterative solver dependant on recorded propellant line stagnation pressures. Primary rocket flow produced thrust ranging from 14 to 17.9lbf. Primary mass flow rate through testing ranged from 0.071 to 0.085lbm/s with calculated chamber pressures between 298-362psia. Calculated primary flow velocity ranged from 6,600ft/s to 8,000ft/s depending on propellant pressure inputs and calculated chamber conditions. The AAR test apparatus was capable of testing various mixing duct geometries and measuring the axial thrust of the mixing ducts separately from the total thrust of the system. Two mixing duct geometries, a straight wall mixing duct and diverging wall mixing duct, with identical exterior dimensions and inlet geometry were tested for a range of air/fuel mixture ratios from 0.82 to 2.2 spanning the stoichometric mixture ratio of 1.5. Mixing duct thrust did not vary greatly with primary flow characteristics. Straight mixing duct thrust averaged 0.97lbf and diverging mixing duct thrust averaged 0.18lbf. Total system thrust decreased by an average of 0.62lbf with a straight mixing duct and 0.74lbf with a diverging mixing duct. Decreases in total thrust are attributed to low pressure flow interaction between the mixing duct and the primary rocket assembly. Visual flow comparison between mixing duct configurations and fuel ratio cases were carried out using high definition video recording with a grid reference for comparison. The diverging mixing duct produced the greatest variation in visible flow when compared to a straight mixing duct and no mixing duct configuration. This indicated that the diverging mixing duct had a greater influence on primary and secondary flow field mixing than the straight mixing duct.

A theoretical investigation of acoustic wave interactions with turbulent premixed flames was performed. Such interactions affect the characteristic unsteadiness of combustion processes, e.g., combustion instabilities. The small perturbation method (SPM) was utilized to evaluate the scattered fields as a result of the flame-wave interaction at the instantaneous wrinkling surface of a randomly moving turbulent flame. Stochastic analysis of ensemble-averaged net acoustic energy was conducted to examine coherent and incoherent acoustic energy amplification /damping by the interaction. Net acoustic energy flux out of the flame is due to two factors: the acoustic velocity jump due to unsteady heat release from flame. The other is the flames unsteady motion. Five(5) dimensionless parameters that govern this net acoustic energy were determined: rms height and correlation length of flame front, incident wave frequency, the ratio of flames diffusion time to flame fronts correlation time, and incidence angle. The dependence of net acoustic energy upon these dimensionless parameters was illustrated and discussed by numerical simulations in case of Gaussian statistics of flame front. The laminar flame response to equivalence ratio perturbations was also examined, showing that the overall heat release response is controlled by the superposition of three disturbances: heat of reaction, flame speed, and flame area. Heat of reaction disturbances dominate the flame response at low Strouhal numbers, roughly defined as (frequency x flame length)/(axial flow velocity). All three disturbances play equal roles at Strouhal numbers of O(1). In addition, the mean equivalence ratio exerts little effect upon this transfer function at low Strouhal numbers. At O(1) Strouhal numbers, the flame response increases with decreasing values of the mean equivalence ratio.

A duração da combustão tem implicação direta na determinação do trabalho negativo no ciclo motor. A duração da combustão tem relação inversa com a velocidade de propagação da chama. Assim, quanto maior a velocidade de propagação da chama, menor a duração da combustão. Além disto, a duração da combustão está relacionada com a relação volumétrica de compressão, com a razão de mistura e com o tipo de combustível, entre outros fatores. Neste sentido, quanto maior a velocidade de queima da mistura ar-combustível, menor o trabalho negativo no ciclo. Neste contexto, foram ensaiadas 3 relações de compressão e 3 razões de mistura, para 6 combustíveis de composição conhecida: gasolina comum tipo C, álcool etílico hidratado combustível (AEHC) e AEHC adicionado à gasolina comum tipo C nas proporções de 20%, 40%, 60% e 80%. A variação da pressão no interior da câmara de combustão, para todos os combustíveis, e a posição da centelha de ignição foram determinadas com a utilização da base angular e com variação da relação volumétrica de compressão e da razão de mistura. O diagrama , para fins de cálculo de área, foi traçado por pós-processamento. Os resultados obtidos indicam que a duração da combustão aumenta com o aumento da razão de mistura e diminui com o aumento da relação volumétrica de compressão, para todos os combustíveis ensaiados. Verificou-se que a amplitude da pressão, no interior da câmara de combustão, se comporta inversamente à duração da combustão. Mostrou-se que o aumento da razão de mistura implica na redução do trabalho líquido entregue ao êmbolo ao longo de todo o ciclo do motor. Opostamente ocorre com o aumento da relação volumétrica de compressão, que implica no aumento do trabalho líquido por ciclo. Concluiu-se que o máximo valor para o trabalho líquido ao longo de todo o ciclo foi obtido para a maior relação volumétrica de compressão (8:1) e a menor razão de mistura (λ = 0,9). O combustível que representou este resultado foi o álcool etílico hidratado combustível adicionado à gasolina comum tipo C em 80% (AEHC80). O mínimo valor para o trabalho líquido, ao longo de todo o ciclo foi obtido, para a menor relação volumétrica de compressão (6:1) e a maior razão de mistura dos ensaios (λ = 1,1). O combustível que representou este resultado foi o álcool etílico hidratado combustível (AEHC). / The duration of the combustion is directly implicative on determining the negative work of the motor cycle. The duration of the combustion has an inverse relation with the flame propagation speed. Thus, the higher propagation of the flame, the shorter duration of the combustion. Besides that, the duration of the combustion is related to the relation of compression, to the air/fuel relation and to the type of fuel, among other factors. In this way, the higher burning speed of the air/fuel mixture, the smallest negative work in the cycle. In such a context, there were tried three compression relations and three mixture ratios for six fuels of know compositions: ordinary gasoline C type, combustible hydrated ethyl alcohol and combustible hydrated ethyl alcohol added to ordinary gasoline C type in the proportions of 20%, 40%, 60% and 80%. The pressure variation inside the combustion chamber, for all fuels, and the position of the ignition spark were determined using the angular base and with variation of the compression relation and the mixture ratio. The diagram, for area calculation, was traced by post processing. The obtained results indicate that the combustion duration increases with the rising of the mixture ratio and decreases with the rising of the compression relation, for all the tried combustibles. It was found that the pressure amplitude inside the combustion chamber behaves inversely to the combustion duration behavior. It was shown that the rising of the mixture ratio implies on the reduction of the net work delivered by the piston all through the cycle of the motor. The opposite occurs with the rising of the compression relation, that implies on the increase of the net work by cycle. It was concluded that the maximum value for the net work all through the cycle was obtained for the higher compression relation (8:1) and the least mixture ratio of the tests (λ = 0,9). The combustible that achieved such a result was the combustible hydrated ethyl alcohol added to ordinary gasoline C type in 80%. The least value for the net work all through the cycle was obtained by the least compression relation (6:1) and the highest mixture ratio of the tests (λ = 1,1). The fuel that achieved that result was the combustible hydrated ethyl alcohol.

A duração da combustão tem implicação direta na determinação do trabalho negativo no ciclo motor. A duração da combustão tem relação inversa com a velocidade de propagação da chama. Assim, quanto maior a velocidade de propagação da chama, menor a duração da combustão. Além disto, a duração da combustão está relacionada com a relação volumétrica de compressão, com a razão de mistura e com o tipo de combustível, entre outros fatores. Neste sentido, quanto maior a velocidade de queima da mistura ar-combustível, menor o trabalho negativo no ciclo. Neste contexto, foram ensaiadas 3 relações de compressão e 3 razões de mistura, para 6 combustíveis de composição conhecida: gasolina comum tipo C, álcool etílico hidratado combustível (AEHC) e AEHC adicionado à gasolina comum tipo C nas proporções de 20%, 40%, 60% e 80%. A variação da pressão no interior da câmara de combustão, para todos os combustíveis, e a posição da centelha de ignição foram determinadas com a utilização da base angular e com variação da relação volumétrica de compressão e da razão de mistura. O diagrama , para fins de cálculo de área, foi traçado por pós-processamento. Os resultados obtidos indicam que a duração da combustão aumenta com o aumento da razão de mistura e diminui com o aumento da relação volumétrica de compressão, para todos os combustíveis ensaiados. Verificou-se que a amplitude da pressão, no interior da câmara de combustão, se comporta inversamente à duração da combustão. Mostrou-se que o aumento da razão de mistura implica na redução do trabalho líquido entregue ao êmbolo ao longo de todo o ciclo do motor. Opostamente ocorre com o aumento da relação volumétrica de compressão, que implica no aumento do trabalho líquido por ciclo. Concluiu-se que o máximo valor para o trabalho líquido ao longo de todo o ciclo foi obtido para a maior relação volumétrica de compressão (8:1) e a menor razão de mistura (λ = 0,9). O combustível que representou este resultado foi o álcool etílico hidratado combustível adicionado à gasolina comum tipo C em 80% (AEHC80). O mínimo valor para o trabalho líquido, ao longo de todo o ciclo foi obtido, para a menor relação volumétrica de compressão (6:1) e a maior razão de mistura dos ensaios (λ = 1,1). O combustível que representou este resultado foi o álcool etílico hidratado combustível (AEHC). / The duration of the combustion is directly implicative on determining the negative work of the motor cycle. The duration of the combustion has an inverse relation with the flame propagation speed. Thus, the higher propagation of the flame, the shorter duration of the combustion. Besides that, the duration of the combustion is related to the relation of compression, to the air/fuel relation and to the type of fuel, among other factors. In this way, the higher burning speed of the air/fuel mixture, the smallest negative work in the cycle. In such a context, there were tried three compression relations and three mixture ratios for six fuels of know compositions: ordinary gasoline C type, combustible hydrated ethyl alcohol and combustible hydrated ethyl alcohol added to ordinary gasoline C type in the proportions of 20%, 40%, 60% and 80%. The pressure variation inside the combustion chamber, for all fuels, and the position of the ignition spark were determined using the angular base and with variation of the compression relation and the mixture ratio. The diagram, for area calculation, was traced by post processing. The obtained results indicate that the combustion duration increases with the rising of the mixture ratio and decreases with the rising of the compression relation, for all the tried combustibles. It was found that the pressure amplitude inside the combustion chamber behaves inversely to the combustion duration behavior. It was shown that the rising of the mixture ratio implies on the reduction of the net work delivered by the piston all through the cycle of the motor. The opposite occurs with the rising of the compression relation, that implies on the increase of the net work by cycle. It was concluded that the maximum value for the net work all through the cycle was obtained for the higher compression relation (8:1) and the least mixture ratio of the tests (λ = 0,9). The combustible that achieved such a result was the combustible hydrated ethyl alcohol added to ordinary gasoline C type in 80%. The least value for the net work all through the cycle was obtained by the least compression relation (6:1) and the highest mixture ratio of the tests (λ = 1,1). The fuel that achieved that result was the combustible hydrated ethyl alcohol.

A duração da combustão tem implicação direta na determinação do trabalho negativo no ciclo motor. A duração da combustão tem relação inversa com a velocidade de propagação da chama. Assim, quanto maior a velocidade de propagação da chama, menor a duração da combustão. Além disto, a duração da combustão está relacionada com a relação volumétrica de compressão, com a razão de mistura e com o tipo de combustível, entre outros fatores. Neste sentido, quanto maior a velocidade de queima da mistura ar-combustível, menor o trabalho negativo no ciclo. Neste contexto, foram ensaiadas 3 relações de compressão e 3 razões de mistura, para 6 combustíveis de composição conhecida: gasolina comum tipo C, álcool etílico hidratado combustível (AEHC) e AEHC adicionado à gasolina comum tipo C nas proporções de 20%, 40%, 60% e 80%. A variação da pressão no interior da câmara de combustão, para todos os combustíveis, e a posição da centelha de ignição foram determinadas com a utilização da base angular e com variação da relação volumétrica de compressão e da razão de mistura. O diagrama , para fins de cálculo de área, foi traçado por pós-processamento. Os resultados obtidos indicam que a duração da combustão aumenta com o aumento da razão de mistura e diminui com o aumento da relação volumétrica de compressão, para todos os combustíveis ensaiados. Verificou-se que a amplitude da pressão, no interior da câmara de combustão, se comporta inversamente à duração da combustão. Mostrou-se que o aumento da razão de mistura implica na redução do trabalho líquido entregue ao êmbolo ao longo de todo o ciclo do motor. Opostamente ocorre com o aumento da relação volumétrica de compressão, que implica no aumento do trabalho líquido por ciclo. Concluiu-se que o máximo valor para o trabalho líquido ao longo de todo o ciclo foi obtido para a maior relação volumétrica de compressão (8:1) e a menor razão de mistura (λ = 0,9). O combustível que representou este resultado foi o álcool etílico hidratado combustível adicionado à gasolina comum tipo C em 80% (AEHC80). O mínimo valor para o trabalho líquido, ao longo de todo o ciclo foi obtido, para a menor relação volumétrica de compressão (6:1) e a maior razão de mistura dos ensaios (λ = 1,1). O combustível que representou este resultado foi o álcool etílico hidratado combustível (AEHC). / The duration of the combustion is directly implicative on determining the negative work of the motor cycle. The duration of the combustion has an inverse relation with the flame propagation speed. Thus, the higher propagation of the flame, the shorter duration of the combustion. Besides that, the duration of the combustion is related to the relation of compression, to the air/fuel relation and to the type of fuel, among other factors. In this way, the higher burning speed of the air/fuel mixture, the smallest negative work in the cycle. In such a context, there were tried three compression relations and three mixture ratios for six fuels of know compositions: ordinary gasoline C type, combustible hydrated ethyl alcohol and combustible hydrated ethyl alcohol added to ordinary gasoline C type in the proportions of 20%, 40%, 60% and 80%. The pressure variation inside the combustion chamber, for all fuels, and the position of the ignition spark were determined using the angular base and with variation of the compression relation and the mixture ratio. The diagram, for area calculation, was traced by post processing. The obtained results indicate that the combustion duration increases with the rising of the mixture ratio and decreases with the rising of the compression relation, for all the tried combustibles. It was found that the pressure amplitude inside the combustion chamber behaves inversely to the combustion duration behavior. It was shown that the rising of the mixture ratio implies on the reduction of the net work delivered by the piston all through the cycle of the motor. The opposite occurs with the rising of the compression relation, that implies on the increase of the net work by cycle. It was concluded that the maximum value for the net work all through the cycle was obtained for the higher compression relation (8:1) and the least mixture ratio of the tests (λ = 0,9). The combustible that achieved such a result was the combustible hydrated ethyl alcohol added to ordinary gasoline C type in 80%. The least value for the net work all through the cycle was obtained by the least compression relation (6:1) and the highest mixture ratio of the tests (λ = 1,1). The fuel that achieved that result was the combustible hydrated ethyl alcohol.

Deep Mixing involves the introduction of cementitious or specially formulated solutions directly into the ground through the use of purpose built blending injection augers. The system is mainly designed to increase strength and reduce compressibility of treated soil. In the first stage of the research effective mixture ratios and mixture types of stabilizing agents were investigated for soft clays (CL form Eymir lake and kaolinite) by means of unconfined compression (UC) tests on stabilized soils. The unconfined compressive strength (UCS) values were obtained for 7,28,90 and 365 days of curing time. The ratio of elastic modulus at 50% failure load (E50) to (UCS) of the stabilizing agents were also investigated. In the second part of the research programme, deep mixed model columns with the three column materials and four different column spacings are formed within the large scale consolidation tanks, and the consolidation characteristics of deep mixed improved clay were investigated. Based on the results of large scale consolidation tests on deep mixed columnar improved soft clay, compressibility characteristics of improved soft clay were determined in relation to spacing of columns namely, effective replacement ratio and binder content. The cement content (also UCS) of the column material was found to be the most important parameter for the improvement effects of DMM applications. Validity of the relations for the estimation of bulk compression modulus of soilcrete were discussed. The use of constrained modulus of the soil and the column material were found to be effective in predicting the compression modulus of the soilcrete. Settlement reduction factor versus replacement ratio and cement content relations were determined which may be used for preliminary design works. The stresses on the soil and the columns were backcalculated from the settlement values. The stress ratios were obtained.