Throttle Air Research Articles

Experimental Study on the Influence of Air Conveyor System Parameters on Vibration of Glass Substrate

In this paper, the method of experimental research is used to minimize the micro-vibration amplitude of 0.6 mm thick glass substrates in the air conveyor system. The optimal parameter combination of the small orifice throttling glass substrate air conveyor system is obtained as follows: orifice diameter 0.25 mm, orifice spacing 60 mm and air-film thickness 50 μm. Secondly, based on the orthogonal experimental data, the influence of the main parameters of the air conveyor system at the micro vibration of the glass substrate is analyzed by variance analysis technology. The results show that the three principal parameters of the air conveyor system have significant influence on the vibration of the glass substrate. Among them, the thickness of the air-film has the greatest influence on the vibration of the glass substrate, the diameter of the orifice has the second influence, and the spacing of the orifice has the least influence. Finally, the influence of the three key parameters of orifice diameter, orifice spacing and film thickness on the micro vibration of glass substrate in the orifice throttling air flotation support system was studied and discussed, and the relationship curves between the maximum amplitude of micro-vibration of glass substrate and the main parameters of air flotation system were obtained.

Engine Indicated Torque Estimation of a Naturally Aspired Gasoline Engine

The information of clutch transmitted torque is needed when controlling a clutch in a vehicle powertrain. However, engine indicated torque is a very important variable when estimating the clutch torque. The engine indicated torque is generally estimated as a function of engine rotational speed and the mass flow rate of air from an intake manifold into cylinders, which is referred as port air mass flow. The port air mass flow cannot be measured but should be estimated in a real vehicle. In previous studies, the port air mass flow was estimated using the information of the mass flow rate of air into the intake manifold through a throttle plate, which is referred as throttle air mass flow, and the information of air pressure in the intake manifold together. However, this study proposes a new estimation method of the port air mass flow using only the information of the throttle air mass flow. In addition, the engine indicated torque is estimated using the estimated port air mass flow and compared with the measured value. The estimation method of the port air mass flow and engine indicated torque, presented in this study, is verified with production engine experiments.

Investigation of Combustion Characteristics in a Kerosene-Fueled Supersonic Combustor with Air Throttling

The paper presents the results of an experimental and numerical study on the combustion characteristics of a supersonic combustor operation enhanced by pilot hydrogen and air throttling, including ignition and combustion. Wall pressure measurements, schlieren images, and hydroxyl-radical planar-laser-induced-fluorescence (OH-PLIF) are used to obtain information on the flowfield and flame development. With the aid of air throttling, the kerosene is ignited by the pilot flame; and the kerosene flame remains stable even after the pilot hydrogen is switched off. The speed of the shock train generated by the throttling air and combustion is about in the expansion section but only about in the cavity region. The stable flame and flame blowout cases can be separated by a curve in a plot of the coexistence time of pilot hydrogen and throttling air versus the air throttling flux ratio. There is a special case lying on this curve for which the flame is unstable and will be blown out before the throttling air is switched off. It is also found that the position of the thermal throat is the same for all the subsonic combustion cases: about 595 mm downstream of the scramjet entrance.

Control of the Formation of a Transonic Region in an Axisymmetric Supersonic Flow with the Use of a Jet and a Near-Wall Energy Supply

The control action of a throttling air jet produced by a gas generator and of the energy sources positioned at the walls of an axisymmetric channel, which models the combustion-chamber unit of a ramjet in which a gas flow is decelerated, on the shock-wave structure of a supersonic gas flow in the channel was investigated for the purpose of formation of a lengthy transonic region in it. A heat energy was supplied to the gas flow in the indicated channel in the pulse-periodic regime, and the pressure in the gas generator was also changed periodically. The range of energies corresponding to a stable transonic flow regime in the channel was determined on the basis of solution of the nonstationary Euler equations in dimensionless variables. For comparison, the combustion of a gaseous fuel inflowing to the channel through a slot in the channel wall upstream of the control air jet was considered. A nonstationary gas flow in the channel was calculated on the basis of the Reynolds-averaged Navier–Stokes equations with the use of the k–ω SST model of turbulence. It is shown that a controllable energy release in the channel, providing the obtaining of a transonic flow regime in it analogous to that obtained on the basis of solution of the Euler equations, can be realized with the use of a control transverse air jet.

Modeling and Simulation Study of Intake System Characteristics of Wankel Engine for UAV

Starting from the actual working process of Wankel engine, the intake system model of Wankel engine is constructed based on the mean value engine model. The parameters to be determined in the model are identified by the least-square method based on the engine test data. According to the nonlinear characteristics of the intake system, the structure of the model is improved by introducing the speed correction term, and the problem that the error of original throttle air mass flow model is larger under the larger throttle opening is solved. The results of simulation and steady-state test show that the maximum relative error between simulation and experimental values of throttle air mass flow is less than +3% and that between simulation and experiment values of intake pressure is less than +2%.The parameter identification and structure of the model have high precision, which can calculate the basic air intake flow of Wankel engine accurately and shorten the development cycle of the electric control system of Wankel engine.

Calculations of shock-wave flow structure in axisymmetric channel with near-wall ethylene burning with throttle air jet

The CFD modelling of the ramjet start with low losses of the stagnation pressure was carried out. The basic feature of this start technology was the jet of compressed air creating effect of a throttle which aids in preliminary decelerating of the flow up to transonic velocities. The comparison with experiment was performed for the hydrogen burning. We studied the axial and near-wall supply of gas fuel. The physical mechanisms stimulating stable presence of transonic mode in the part with constant section were investigated within the frameworks URANS approach. It was shown that fuel supply blockage is a way to control near-wall supplying of gaseous fuel at considerably low pressure falls. And blocking the ignition processes is a way to control the axial supply at quite high pressure falls.

Experimental study on the effects of simulated flight conditions on ignition and flame stabilization in a supersonic combustor

Effects of simulated flight conditions on ignition and flame stabilization in a kerosene fueled scramjet combustor were experimentally investigated in the present paper. Simulated flight conditions were Mach 4.5 and Mach 4.0, and the isolator entrance Mach number was 2.0. Wall pressure and flame emission were made during the experiments in an attempt to better understand the combustion characteristics, air throttling was used to enhance the flame stabilization. The results showed that, the kerosene ignition was achieved successfully under the Mach 4.5 flight condition, that of Mach 4.0 flight condition was blowout before the kerosene pressure reached the max pressure. The flame in the combustor without air throttling during Mach 4.0 flight condition only existed in the cavity and near the top wall before it was blown off, that of Mach 4.5 flight condition had spread into the isolator. The flame stabilization was also only achieved under the Mach 4.5 flight condition with the aid of air throttling, the flame in the combustor with air throttling during the Mach 4.0 flight condition was blowout before the throttling air was removed. Ignition and flame stabilization were easy to be achieved under the higher flight condition.

Investigation of ignition characteristics in a kerosene fueled supersonic combustor

Ignition characteristics of a kerosene fueled supersonic combustor has been numerically and experimentally investigated in the present paper. Flame luminosity images and wall pressure measurements are used for better understanding the ignition and combustion characteristics, air throttling is used to enhance ignition in the combustor. The results are obtained under the inflow condition of Ma number 2.0, total pressure 1.0 MPa and total temperature 1100 K which corresponds to Ma4.5 flight condition. When the ER (Equivalence Ratio) of kerosene is 0.19, the kerosene cannot be ignited at all only by the spark plug. When the flux ratio of air throttling (the ratio of mass flux of air throttling to mass flux of the inflow air) is 9.1%, a small part of kerosene can be ignited, but the flame is blown off soon. When the throttling air flux ratio is increased to 13.7% or 24.5%, the kerosene can be ignited successfully, and the combustion is stable and intense. Cold room temperature liquid kerosene can be ignited successfully by the spark plug with the aid of the throttling air.

Experimental study on flame development and stabilization in a kerosene fueled supersonic combustor

Flame development and stabilization in a kerosene fueled supersonic combustor with air throttling were experimentally investigated in the present paper. Stagnation conditions were 1100 K and 1.0 MPa and Mach number at the isolator entrance was 2.0. Various measurements included schlieren, shadow, interferometry, flame emission and PLIF were made during the experiments in an attempt to better understand the combustion flow field. The flow structure of non-reacting flow with and without air throttling was investigated firstly, the results showed a shock train was generated due to the increased back pressure by the throttling air, shock waves of the two cases oscillated with the flow. The flame development of pilot hydrogen was studied secondly, the ER (Equivalence Ratio) of pilot hydrogen should be 0.1, because a stable flame was beneficial to ignition transient. Finally, the effects of air throttling on flame stabilization were investigated, time for ignition of the case with air throttling was nearly a third of the case without air throttling, the pilot flame was blown off by the room temperature kerosene. But the kerosene was ignited successfully by the pilot hydrogen with the aid of air throttling, and even when the throttling air was removed, the flame was still stable.

EVALUATION OF DIFFERENT TECHNIQUES TO SPRAY THE COMPOST TEA FOR ORCARD TREES

The conventional sprayers, such as the gun sprayers were applied for the apple trees under Egyptian conditions. In organic apple production the growers tends to apply the compost tea as provide fertilizer and pesticides control. The objectives of this current research were to spray the compost tea by using the gun sprayer, air assisted backpack sprayer Suzuki (2.13 kW) and Tiazh. Qinili Machinery Knapsack. Also, investigated to use the yeast with the compost tea to improve and increase nutrient availability. The different techniques sprayers an air assisted backpack sprayer Suzuki (2.13 kW) and Tiazh. Qinili Machinery Knapsack sprayer (0.7 kW) achieving thorough coverage was compared to a conventional hydraulic sprayer (gun sprayer) to apply the bio fertilizer compost tea. Two different composts tea, the aerated compost tea (ACT1) and nun-aerated compost tea (ACT2), were applied under laboratory conditions. The 10 gm of yeast/10 liter was added for both compost teas (ACT) as the marker of the microorganism in the compost tea. Microscope with digital camera and software Image J V1.52 program was used to count the yeasts cells before and after spray treatment conditions. The conventional hydraulic sprayer (gun sprayer) gave a good result to apply the compost tea with low values of number of microorganisms (yeast cells). The low values of yeasts after treated main that there are a highest damage or crushed of yeast cells and the nutrition will be increasing. The viability numbers of yeast cells for conventional gun sprayer in ACT1 compost tea were 0.76 x 106 / ml and 0.52 x 106 / ml at operating pressure 390 kPa and 480 kPa respectively. As well as, the viability numbers of yeast cells for conventional gun sprayer in ACT2 compost tea were 0.84 x 106 / ml and 0.76 x 106 / ml at operating pressure 390 kPa and 480 kPa respectively. The values of number of yeast cells for ACT1 were 0.52 x 106 /ml, 2.60 x 106 / ml and 1.22 x 106 / ml for conventional sprayer, motorized an air assisted backpack sprayer Suzuki with 2.13 kW power and Tiazh Qinili Machinery Knapsack sprayer with 0.7 kW power respectively. The viability numbers of yeast cells for ACT2 were 0.63 x 106/ ml, 1.06 x 106 / ml and 0.82 x 106 / ml for conventional sprayer, motorized an air assisted backpack Suzuki sprayer and Tiazh Qinili Machinery Knapsack sprayer respectively.The viability numbers of yeast cells for the air assisted backpack Suzuki sprayer were 2.3 x 106 / ml and 4.6 x 106 / ml for ACT1 and ACT2 compost tea at half open throttle air position respectively.The conventional gun sprayer produced highly values of damage percentage compared to the T.Qinili sprayer and Suzuki sprayer. The percentage of damage yeasts cell in ACT1 were 97.25% and 96.08 % at operating pressure 480 kPa and 390 kPa respectively.

Study on flame stabilization of a hydrogen and kerosene fueled combustor

Flame stabilization of a hydrogen and kerosene fueled combustor was experimentally and numerically studied in the present paper for a simulated flight Mach number 4.5. The results were obtained under the inflow conditions of Mach number of 2.0, static temperature of 656.5 K and static pressure of 0.125 MPa respectively. An air throttle was used as an independent backpressure source to generate a shock train which was used to achieve flame stabilization, and the location of air throttling was 575 mm downstream the combustor entrance. Our results indicated that the equivalence ratio (ER) of hydrogen and kerosene had a big effect on flame stabilization, when the ER of hydrogen was 0.11, the kerosene (ER: 0.16) could be ignited successfully by the hydrogen pilot flame without air throttling, but the flame of kerosene/air was unstable, and it would be blown off later. When the ER of hydrogen had been increased to 0.22, the flame of kerosene (ER: 0.16 and 0.25) and air mixture was stable without air throttling. But when the ER of kerosene was increased to 0.45, the kerosene/air could not be ignited at all and the pilot flame was blown off by the unheated kerosene also without air throttling. Shock waves generated due to the increased back pressure by the throttling air, which decelerated the high-speed main stream, and increased the temperature and pressure in the combustor. The cavity shear layer was lifted into the core flow, which would enhance the fuel/air mixing efficiency. Then the kerosene (ER: 0.45) could be ignited successfully by the hydrogen pilot flame (ER: 0.22), and the flame stabilization was also achieved by the throttling air.

Numerical study on effect of air throttling on combustion mode formation and transition in a dual-mode scramjet combustor

Air throttling has a great effect on combustion mode formation and transition in a dual-mode scramjet combustor. An unsteady CFD method was used to investigate this effect in the present paper. The simulation was carried out under the inflow conditions of Mach number of 2.0, static temperature of 656.5 K and static pressure of 0.125 MPa respectively. The location of air throttling was 575 mm downstream the combustor entrance. Our results indicated that the combustion mode could change from supersonic combustion to subsonic combustion with throttling air injected into the combustor. Without air throttling, the combustion flame was extinguished near the down wall of the combustor, which was corresponding to the supersonic combustion mode. With air throttling, the flame was stabilized near the down wall of the combustor, which was corresponding to the subsonic combustion mode. The mode transition was mainly effected by two parameters: the mass flux of throttling air and the throttling off time. A higher wall pressure was generated by a larger mass flux of air throttling, then the combustion mode transition was easy to be achieved. The combustion heat release was insufficient when the air throttling off time was shorter than usual.

Ignition Transients in a Scramjet Engine with Air Throttling Part II: Reacting Flow

The analysis presented in Part I of this study is extended to investigate ignition transients and flame development in an ethylene-fueled scramjet engine. Unheated gaseous ethylene is transversely injected into the combustor upstream of a recessed cavity flameholder. Immediately after the ethylene–air mixture reaches its steady state in the combustor, a hotspot igniter is activated in the cavity to initiate chemical reactions. Cases both with and without air throttling downstream of the cavity during the engine startup stage are examined in detail. Successful ignition can only be achieved with the aid of air throttling under the present flow conditions. As a consequence of the backpressurization by the throttling air, a shock train is generated in the isolator, which then decelerates the high-speed main stream, enhances the fuel mixing efficiency, and increases the temperature and pressure in the combustor. Chemical reactions are intensified and produce sufficient heat release to maintain a flow environment conducive to flame stabilization. A self-sustaining mechanism is thus established between the flow and flame development. Stable flames are achieved even after the deactivation of air throttling. The predicted pressure distribution along the entire flowpath agrees well with experimental measurements.

Robust Engine Torque Control by Discrete Event Disturbance Observer

A model-based approach is applied to robustly control torque generation in four-stroke spark ignition (SI) engines. Discrete event engine model (DEM) is adopted to describe the torque generation process consisting of discrete combustion strokes. Disturbance observer (DOB) is utilized to achieve robust stability and performance of the torque generation process. For a single-input, single-output model with throttle air intake as input and generated torque as output, the desired plant behavior is stably realized by the DOB over a desired frequency band which is sufficient for powertrain control applications. Numerical and experimental results show the effectiveness of the proposed DOB scheme.