Collisional-Radiative Recombination of Ions and Electrons in High-Pressure Plasmas in Which the Electron Temperature Exceeds the Gas Temperature

1969 ◽  
Vol 177 (1) ◽  
pp. 254-257 ◽  
Author(s):  
C. B. Collins
Keyword(s):  
High Pressure ◽  
Electron Temperature ◽  
Radiative Recombination ◽  
Gas Temperature

Experimental investigation of wall heat transfer due to spray combustion in a high-pressure/high-temperature vessel

2021 ◽  
pp. 146808742110072
Author(s):  
Karri Keskinen ◽  
Walter Vera-Tudela ◽  
Yuri M Wright ◽  
Konstantinos Boulouchos
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
High Pressure ◽  
High Temperature ◽  
High Speed ◽  
Transfer Problem ◽  
Wall Heat Transfer ◽  
Gas Temperature ◽  
Reference Case ◽  
High Pressure High Temperature

Combustion chamber wall heat transfer is a major contributor to efficiency losses in diesel engines. In this context, thermal swing materials (adapting to the surrounding gas temperature) have been pinpointed as a promising mitigative solution. In this study, experiments are carried out in a high-pressure/high-temperature vessel to (a) characterise the wall heat transfer process ensuing from wall impingement of a combusting fuel spray, and (b) evaluate insulative improvements provided by a coating that promotes thermal swing. The baseline experimental condition resembles that of Spray A from the Engine Combustion Network, while additional variations are generated by modifying the ambient temperature as well as the injection pressure and duration. Wall heat transfer and wall temperature measurements are time-resolved and accompanied by concurrent high-speed imaging of natural luminosity. An investigation with an uncoated wall is carried out with several sensor locations around the stagnation point, elucidating sensor-to-sensor variability and setup symmetry. Surface heat flux follows three phases: (i) an initial peak, (ii) a slightly lower plateau dependent on the injection duration, and (iii) a slow decline. In addition to the uncoated reference case, the investigation involves a coating made of porous zirconia, an established thermal swing material. With a coated setup, the projection of surface quantities (heat flux and temperature) from the immersed measurement location requires additional numerical analysis of conjugate heat transfer. Starting from the traces measured beneath the coating, the surface quantities are obtained by solving a one-dimensional inverse heat transfer problem. The present measurements are complemented by CFD simulations supplemented with recent rough-wall models. The surface roughness of the coated specimen is indicated to have a significant impact on the wall heat flux, offsetting the expected benefit from the thermal swing material.

scholarly journals Harvesting the Potential of CO2 before it is Injected into Geological Reservoirs

2021 ◽  
Vol 3 (4) ◽  
pp. 1-1
Author(s):  
Tran X Phuoc ◽  
◽  
Mehrdad Massoudi ◽  
Keyword(s):  
High Pressure ◽  
Mechanical Work ◽  
Lower Pressure ◽  
Co2 Injection ◽  
Gas Temperature ◽  
Expansion Valve ◽  
Useful Power ◽  
Turbine Disks ◽  
Pressure Transport ◽  
The Cost

To store CO2 in geological reservoirs, expansion valves have been used to intentionally release supercritical CO2 from high-pressure containers at a source point to lower-pressure pipelines and transport to a selected injection site. Using expansion valves, however, has some shortcomings: (i) the fluid potential, in the form of kinetic energy and pressure which can produce mechanical work or electricity, is wasted, and (ii) due to the Joule-Thomson cooling effect, the reduction in the temperature of the released CO2 stream might be so dramatic that it can induce thermal contraction of the injection well causing fracture instability in the storage formation. To avoid these problems, it has been suggested that before injection, CO2, should be heated to a temperature slightly higher than that of the reservoir. However, heating could increase the cost of CO2 injection. This work explores the use of a Tesla Turbine, instead of an expansion valve, to harvest the potential of CO2, in the form of its pressure and kinetics, to generate mechanical work when it is released from a high-pressure container to a lower-pressure transport pipeline. The goal is to avoid throttling losses and to produce useful power because of the expansion process. In addition, due to the friction between the gas and the turbine disks, the expanded gas temperature reduction is not as dramatic as in the case when an expansion valve is used. Thus, as far as CO2 injection is concerned, the need for preheating can be minimized.

scholarly journals Analisis Pengaruh High Pressure Compressor Rotor Clearance Terhadap Exhaus Gas Temperature Margin pada CFM56-7

2021 ◽  
Vol 6 (2) ◽  
pp. 50-55
Author(s):  
Wildan Sofary Darga ◽  
Edy K. Alimin ◽  
Endah Yuniarti
Keyword(s):  
High Pressure ◽  
Engine Performance ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Compressor Rotor ◽  
High Pressure Compressor ◽  
The Difference ◽  
Gas Turbine Exhaust ◽  
Temperature Margin ◽  
Pressure Compressor

Exhaust Gas Temperatue is an parameter where the hot gases’s temperature leave the gas turbine. Exhaust gas temperature margin is the difference between highest temperature at take off phase with redline on indicator (???????????? ???????????????????????? °????=???????????? ????????????????????????????−???????????? ???????????????? ????????????). EGTM is one of any factor to determine engine performance. A good perfomance of an engine when it has a big margin (EGTM), during operation of an engine the EGTM could decrease untill 0 (zero). So many factors could affect EGTM deteroration there are: distress hardware such as airfoil erosion, leak of an airseals, and increase of clearance between tip balde and shroud. Increase of clearance happens in high pressure compressor rotor clearance. In CFM56-7 have 9 stage(s) of high pressure compressor and each stage give the EGT Loses. The calculation of EGT Effect/Losses is actual celarance – minimum clearance x 1000 x EGT Effect °C, where actual clearance define by the substraction of outside diameter’s rotor with inside diameter’s shroud, minimum clearance define in the manual, 1000 is adjustment from mils/microinch to inch, and EGT Effect is temperature that define in the manual. The analysist had done with 6 (six) engine serial number and proceed by corelation that shown linkage between clearance and EGT Effect, the corelation is strong shown the result of corelation (r) is 0.994275999 or nearest 1.

Application of Ultra-Low NOx Combustor to the MHPS Existing Gas Turbine

2021 ◽  
Author(s):  
Takashi Nishiumi ◽  
Hirofumi Ohara ◽  
Kotaro Miyauchi ◽  
Sosuke Nakamura ◽  
Toshishige Ai ◽  
...  
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Operational Experience ◽  
Emission Rates ◽  
Gas Temperature ◽  
Design Development ◽  
And Control

Abstract In recent years, MHPS achieved a NET M501J gas turbine combined cycle (GTCC) efficiency in excess of 62% operating at 1,600°C, while maintaining NOx under 25ppm. Taking advantage of our gas turbine combustion design, development and operational experience, retrofits of earlier generation gas turbines have been successfully applied and will be described in this paper. One example of the latest J-Series technologies, a conventional pilot nozzle was changed to a premix type pilot nozzle for low emission. The technology was retrofitted to the existing F-Series gas turbines, which resulted in emission rates of lower than 9ppm NOx(15%O2) while maintaining the same Turbine Inlet Temperature (TIT: Average Gas Temperature at the exit of the transition piece). After performing retrofitting design, high pressure rig tests, the field test prior to commercial operation was conducted on January 2019. This paper describes the Ultra-Low NOx combustor design features, retrofit design, high pressure rig test and verification test results of the upgraded M501F gas turbine. In addition, it describes another upgrade of turbine to improve efficiency and of combustion control system to achieve low emissions. Furthermore it describes the trouble-free upgrade of seven (7) units, which was completed by utilizing MHPS integration capabilities, including handling all the design, construction and service work of the main equipment, plant and control systems.

Ionisationsmechanismus in der Relaxationszone schwach instationärer Stoßwellen in Argon und Krypton / Ionisation Mechanism in the Relaxation Zone oj Weakly Instationary Shock Waves in Argon and Krypton

1974 ◽  
Vol 29 (4) ◽  
pp. 568-576 ◽  
Author(s):  
G. Meinhold ◽  
F. Demmig ◽  
W. Bötticher
Keyword(s):  
Shock Waves ◽  
Shock Front ◽  
Electron Temperature ◽  
Excited States ◽  
Gas Temperature ◽  
Electron Collisions ◽  
Step Process ◽  
Gasdynamic Model ◽  
Excitation Processes ◽  
Additional Excitation

The primary ionisation relaxation up to electron densities of ne = 4·1013 cm-3 is investigated by means of 4 mm - microwave - interferometry. The values of the timedependent gas temperature Ta, and gas density na behind the shock front are calculated using a gasdynamic model which strictly takes into account the instationarity of the flow. From the results it is concluded that neither the familiar two step process dominated by atom collisions nor the assumption of additional excitation processes by electron collisions can fully describe the observed ionisation rates. There is evidence that both the ionisation rates and the electron temperature are influenced by transitions between the first four excited states due to superelastic electron collisions. As a result the electron temperature may even exceed the gas temperature.

Gas Turbines for Coal-Fired Turbocharged PFBC Boiler Power Plants

1984 ◽  
Author(s):  
Richard Wenglarz ◽  
Steven Drenker
Keyword(s):  
High Pressure ◽  
Gas Turbines ◽  
Power Plants ◽  
Modular Construction ◽  
Fluidized Bed Combustion ◽  
Gas Temperature ◽  
Utility Industry ◽  
Advantages And Disadvantages ◽  
Construction Methods ◽  
Standard Gas

A coal-fired turbocharged boiler using fluidized bed combustion at high pressure would be more compact than a pulverized coal fired boiler. The smaller boiler size could permit the utility industry to adopt efficient modular construction methods now widely used in other industries. A commercial turbocharger of the capacity needed to run a 250 MWe power plant doe not exist; commercial gas turbines of the correct capacity exist, but they are not matched to this cycle’s gas temperature of less than 538°C (1000°F). In order to avoid impeding the development of the technology, it will probably be desirable to use existing machines to the maximum extent possible. This paper explores the advantages and disadvantages of applying either standard gas turbines or modified standard gas turbines to the turbocharged boiler.

Application of time-division-multiplexed lasers for measurements of gas temperature and CH_4 and H_2O concentrations at 30 kHz in a high-pressure combustor

2010 ◽  
Vol 49 (26) ◽  
pp. 4963 ◽  
Author(s):  
Andrew W. Caswell ◽  
Thilo Kraetschmer ◽  
Keith Rein ◽  
Scott T. Sanders ◽  
Sukesh Roy ◽  
...  
Keyword(s):  
High Pressure ◽  
Gas Temperature ◽  
Time Division
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