The Interaction of a Hot Gas Flow and a Cold Liquid Spray in Channels

1976 ◽  
Vol 98 (3) ◽  
pp. 421-426 ◽  
Author(s):  
I. S. Habib
Keyword(s):  
Gas Flow ◽  
Wall Friction ◽  
Liquid Droplets ◽  
Gas Temperature ◽  
Cooling Process ◽  
Rapid Cooling ◽  
Hot Gas ◽  
Liquid Spray ◽  
Duct Geometry ◽  
Cold Liquid

The coupled interaction of cold liquid sprays and a hot gas stream is analyzed. The effect of liquid droplets introduced into a hot gas stream flowing in channels of constant and of varying areas is investigated as a rapid cooling process for a hot gas discharge. The effects of spray distribution, duct geometry, and wall friction are examined. Variations of gas and liquid spray properties such as gas temperature and velocity, droplets velocity, temperature, and distribution are presented as a function of distance along the duct in the direction of flow. The effectiveness of this rapid cooling process for a hot gas flow is assessed.

IGNITION CONDITIONS OF A SINGLE BORON PARTICLE IN HOT GAS FLOW

2020 ◽  
Author(s):  
G. V. Ermolaev ◽  
◽  
A. V. Zaitsev ◽  
Keyword(s):  
Oxygen Concentration ◽  
Gas Flow ◽  
Flame Temperature ◽  
Combustion Process ◽  
Experimental Studies ◽  
Gas Temperature ◽  
Hot Gas ◽  
Combustion Models ◽  
Boron Particle ◽  
Boron Particles

The basic experimental studies on boron combustion are done with the same general scheme of the experiment. Boron particles are injected into flat-flame burner products with the help of the transporting jet of cold nitrogen. Boron particle combustion process is registered with a number of optical methods. It is proposed that boron particle is injected into the main hot gas flow instantly, combustion takes place at the flame temperature and predefined oxygen concentration, and the influence of the transporting cold nitrogen jet is ignored. Recent combustion models are based mostly on this type of experiments and characterized with high complexity and low prediction level. In our study, we reconstruct the particle injection conditions for several basic experimental papers. It is shown that in all experimental setups, ignition, combustion, and even total particle burnout take place in the wake of the cold nitrogen jet. This zone is characterized with a much lower gas temperature and oxygen concentration than the main flat burner flow. The total temperature decrease can be about several hundred degrees, oxygen concentration can be 30%-50% lower than that used in the previous analysis of the experimental results. The temperatures of ignition and transition to the second stage of combustion are found with the help of the test particle trajectory and temperature tracking. It is shown that analysis of the influence of boron particles injection on gas temperature and oxygen concentration is mandatory for the development of future combustion models.

A Methodology for Measuring Turbocharger Adiabatic Maps in a Gas-Stand and its Usage for Calibrating Control Oriented and 1D Models at Early ICE Design Stages

2019 ◽  
Author(s):  
José Ramón Serrano ◽  
Francisco José Arnau ◽  
Luis Miguel García-Cuevas ◽  
Alejandro Gómez-Vilanova ◽  
Stephane Guilain ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Internal Combustion Engines ◽  
Gas Flow ◽  
System Analysis ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
Boost Pressure ◽  
Gas Temperature ◽  
Hot Gas ◽  
The Impact

Abstract Turbocharged engines are the standard architecture for designing efficient spark ignition and compression ignition reciprocating internal combustion engines (ICE). Turbochargers characterization and modeling are basic tasks for the analysis and prediction of the whole engine system performance and this information is needed in quite early stages of the engine design. Turbocharger characteristics (efficiency, pressure ratio, mass flow rates...) traditionally rely in maps of pseudo non-dimensional variables called reduced variables. These maps must be used by reciprocating ICE designer and modeler not only for benchmarking of the turbocharger, but for a multiplicity of purposes, i.e: assessing engine back-pressure, boost pressure, load transient response, after-treatment inlet temperature, intercooler inlet temperature, low pressure EGR temperature, ... Maps of reduced variables are measured in gas-stands with steady flow but non-standardized fluids conditioning; neither temperatures nor flows. In concrete: turbine inlet gas temperature; lubrication-oil flow and temperature; water-cooling flow and turbo-machinery external heat transfer are non-standardized variables which have a big impact in assessing said multiplicity of purposes. Moreover, adiabatic efficiency, heat losses and friction losses are important data, hidden in the maps of reduced variables, which depend on the testing conditions as much as on the auxiliary fluids temperature and flow rate. In this work it is proposed a methodology to standardize turbochargers testing based in measuring the maps twice: in close to adiabatic and in diathermal conditions. Along the paper it is discussed with special detail the impact of the procedure followed to achieve said quasi-adiabatic conditions in both the energy balance of the turbocharger and the testing complexity. As a conclusion, the paper proposes a methodology which combines quasi-adiabatic tests (cold and hot gas flow) with diathermal tests (hot gas flow) in order to extract from a turbocharger gas-stand all information needed by engine designers interested in controlling or 1D-modelling the ICE. The methodology is completed with a guide for calibrating said control-oriented turbocharger models in order to separate aerodynamic efficiency (adiabatic) from heat transfer losses and from friction losses in the analysis of the turbocharger performance. The outsourced calibration of the turbocharger model allows avoiding uncertainties in the global ICE model calibration, what is very interesting for turbochargers benchmarking at early ICE-turbo matching stages or for global system analysis at early control design stages.

Motion of fine-spray liquid droplets in hot gas flow

2014 ◽  
Vol 21 (5) ◽  
pp. 609-616 ◽  
Author(s):  
G. V. Kuznetsov ◽  
P. A. Kuibin ◽  
P. A. Strizhak
Keyword(s):  
Gas Flow ◽  
Liquid Droplets ◽  
Hot Gas ◽  
Fine Spray

Experimental and Numerical Research on Application of MGC Material for High Temperature Turbine Nozzles

2005 ◽  
Author(s):  
Shu Fujimoto ◽  
Yoji Okita
Keyword(s):  
Gas Flow ◽  
High Strength ◽  
Temperature Fields ◽  
Stress Fields ◽  
Transient Temperature ◽  
Gas Temperature ◽  
Hot Gas ◽  
Numerical Research ◽  
Research On Application ◽  
Resistance Performance

In recent years, a material called MGC (Melt-Growth Composite) has been developed. This material has innovative characteristics such that it can maintain its high strength for up to 1700°C, with an excellent oxidization resistance performance. These characteristics are quite ideal for the gas turbine application. This paper deals with numerical and experimental study on the performance of MGC turbine nozzles conducted in 2003. Firstly the bow stacked solid nozzle has been designed by using numerical analyses under the gas flow condition at 1700°C that is the final target inlet gas temperature of the MGC turbine project (2001–2005). Secondly three MGC nozzles have been manufactured on trial and one of them has been tested in steady hot gas flow at 1500°C that is the target inlet gas temperature in 2003, temperature and stress fields have been evaluated numerically and the design of this MGC turbine nozzle has been validated for the steady gas flow at 1500°C. Furthermore another has been tested under a TRIP condition (TRIP: Emergency engine stop by fuel cutoff) from 1500°C level, transient temperature fields on the nozzle surface have been obtained and temperature and stress fields have been evaluated numerically. This stress analysis shows that quite large stress was generated in the nozzle in the TRIP test and therefore in future newly re-designed shape of MGC turbine nozzles is required.

Formation of Deposits From Heavy Fuel Oil Ash in an Accelerated Deposition Facility at Temperatures Up to 1206°C

2017 ◽  
Author(s):  
Robert G. Laycock ◽  
Thomas H. Fletcher
Keyword(s):  
Gas Turbines ◽  
Gas Flow ◽  
Particle Diameter ◽  
Capture Efficiency ◽  
Fuel Oil ◽  
Nickel Base Superalloy ◽  
Gas Temperature ◽  
Heavy Fuel Oil ◽  
Hot Gas ◽  
Exhaust Stream

Some industrial gas turbines are currently being fired directly using heavy fuel oil, which contains a small percentage of inorganic material that can lead to fouling and corrosion of turbine components. Deposits of heavy fuel oil ash were created in the Turbine Accelerated Deposition Facility (TADF) at Brigham Young University under gas turbine-related conditions. Ash was produced by burning heavy fuel oil in a downward-fired combustor and collecting the ash from the exhaust stream. The mass mean ash particle diameter from these tests was 33 microns. This ash was then introduced into the TADF and entrained in a hot gas flow that varied from 1088 to 1206°C. The gas and particle velocity was accelerated to over 200 m/s in these tests. This particle-laden hot gas stream then impinged on a nickel base superalloy metal coupon approximately 3 cm in diameter, and an ash deposit formed on the coupon. Sulfur dioxide was introduced to the system to achieve 1.1 mol% SO2 in the exhaust stream in order to simulate SO2 levels in turbines currently burning heavy fuel oil. The ash deposits were collected, and the capture efficiency, surface roughness, and deposit composition were measured. The deposits were then washed with deionized water, dried, and underwent the same analysis. It was found that, as the gas temperature increased, there was no effect on capture efficiency and the post-wash roughness of the samples decreased. Washing aided in the removal of sulfur, magnesium, potassium, and calcium.

Gas Temperature Field Measurement Using Thin-Filament Pyrometry

2014 ◽  
Author(s):  
Guanghua Wang ◽  
Carlos Bonilla ◽  
Danielle Kalitan
Keyword(s):  
Radiation Effects ◽  
Thin Filament ◽  
Gas Flow ◽  
Near Infrared ◽  
Flame Temperature ◽  
Band Pass Filter ◽  
Gas Temperature ◽  
Pass Filter ◽  
Hot Gas ◽  
Mach Numbers

Thin Filament Pyrometry (TFP) has been proven to be a useful approach to measure hot gas temperature. The TFP technique involves suspending a thin filament (typically a SiC fiber) in hot gas flow path and calculating the gas temperature from the measured thermal radiance of the filament. Comparing to most optical and laser based non-intrusive techniques, the TFP approach offers significant simplicity, reduced cost and relative ease of applicability, especially at high-pressure gas-turbine type conditions. In this study, TFP was employed to measure combustor exit gas temperature distributions in an atmospheric combustion rig simulating a model aero-engine combustor burning Jet-A fuel. Hot gas from the combustor was accelerated through a converging nozzle to achieve high exit velocities. The thermal radiation signal from the glowing fiber was collected by a Near Infrared (NIR) camera outfitted with a band pass filter. The gas temperature profile was calculated by an intensity ratio technique. Two-Dimensional temperature maps were obtained via spatially and temporally scanning the TFP system. Temperature measurements at the combustor exit are reported for various fuel-air ratios at Mach numbers around 0.38. A type-B thermocouple stationed at the centerline of the combustor exit was corrected for radiation effects and used to infer the flame temperature for TFP measurement. The major contributions of the current study to the advancement of the TFP technique for measuring hot gas temperatures are: (1) To the authors’ knowledge, this is the first time that the TFP technique has been used in a liquid fueled combustion system, and (2) The data presented herein were obtained at greater Mach numbers than all previous studies (Ma = 0.38).

Theoretical Analysis of the Unsteady Gas Flow in the Exhaust System of an Engine

1966 ◽  
Vol 8 (1) ◽  
pp. 70-90 ◽  
Author(s):  
E. H. Wright ◽  
K. F. Gill
Keyword(s):  
Gas Flow ◽  
Flow Theory ◽  
Wall Friction ◽  
Poor Correlation ◽  
Exhaust Pipe ◽  
Gas Temperature ◽  
Rarefaction Waves ◽  
Cross Sectional ◽  
Method Of Solution ◽  
Fluid Properties

The problem studied is that of unsteady gas motion in ducts of both constant and slowly varying cross-sectional area with the effects of wall friction and heat transfer taken into account. The values of the specific heats used in the analysis are those applicable to the instantaneous gas temperature at the instant under consideration, i.e. thermal lags are ignored. To solve the unsteady flow equations, a method is developed based on the theory of characteristics and in the application of this method a pure graphical approach is used for convenience. The plotting technique adopted is the ‘field method of solution’ in which it is assumed that a region of continually varying fluid properties can be broken into a large number of small regions for calculation purposes. The fluid properties are assumed uniform throughout each of these small regions and changes in the fluid properties can only occur across the boundaries or characteristics separating the small regions. With a firing engine, temperature discontinuities will be established at the interface of the hot gases being discharged from the cylinder and the cooler residuals from the previous cycle. Owing to the interaction of successive points of the fundamental pressure pulse with those resulting from the reflection of previous points of the fundamental pulse, sonic velocities can be encountered at the diffuser entry section. The formation of a steep front at the diffuser entry section as a result of these rarefaction waves can produce a shock wave. A method of solution for the existence in the flow of such discontinuities as temperature and shock is included. The general conclusions to be drawn are: (1) true application of the irreversible flow theory gives a good solution of the wave patterns occurring in both the cylinder and exhaust pipe of the engine; (2) the air mass flow can be predicted with good accuracy by application of the irreversible flow theory developed; (3) the poor correlation resulting from application of the isentropic flow theory shows caution should be exercised in the use of this simplified theory.

Nucleation Processes in Large Scale Vapor Explosions

1979 ◽  
Vol 101 (2) ◽  
pp. 280-287 ◽  
Author(s):  
R. E. Henry ◽  
H. K. Fauske
Keyword(s):  
Large Scale ◽  
Interface Temperature ◽  
Liquid Droplets ◽  
Contact Interface ◽  
Vapor Cavity ◽  
Spontaneous Nucleation ◽  
System Pressure ◽  
Nucleation Model ◽  
Vapor Explosions ◽  
Cold Liquid

A spontaneous nucleation model is proposed for the mechanisms which lead to explosive boiling in the free contacting mode. The model considers that spontaneous nucleation cannot occur until the thermal boundary layer is sufficiently thick to support a critical size vapor cavity, and that significant bubble growth requires an established pressure gradient in the cold liquid. This results in a prediction that, for an interface temperature above the spontaneous nucleation limit, large cold liquid droplets will remain in film boiling due to coalescence of vapor nuclei, whereas smaller droplets will be captured by the hot liquid surface and rapidly vaporize, which agrees with the experimental observations. The model also predicts that explosions are eliminated by an elevated system pressure or a supercritical contact interface temperature, and this is also in agreement with experimental data.

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