scholarly journals GAS TEMPERATURE DISTRIBUTION AND EDDY DIFFUSIVITY OF HEAT IN GASEOUS SUSPENSION FLOW

1979 ◽  
Vol 12 (3) ◽  
pp. 183-189 ◽  
Author(s):  
SHIGERU MATSUMOTO ◽  
AKIHIKO TAKAHASHI ◽  
MUTSUMI SUZUKI ◽  
SIRO MAEDA
Author(s):  
Tang Chian-ti

Taking account of the marine gas turbine operation features, the author has chosen the hot corrosion peak temperature of materials as the guide vane material limiting temperature while evaluating the overall temperature distribution factor. Along with the blade cooling effectiveness a safety margin factor has been introduced during its evaluation. The gas temperature distribution along blade height is assumed to satisfy the condition that approximately equal safety factor in respect of strength prevails along blade height. Once the gas radial temperature profile becomes known, the radial temperature distribution factor can be readily determined.


2019 ◽  
Vol 123 (1261) ◽  
pp. 340-355 ◽  
Author(s):  
S. M. Choi ◽  
S. Kim ◽  
R. S. Myong ◽  
W. Kim

ABSTRACTInfrared signal measurements from a micro-turbojet engine are conducted to understand the characteristics of the engine performance and the infrared signal by varying the exhaust nozzle configuration. A cone type nozzle and five rectangle type nozzles whose aspect ratios vary from one to five are used for this experimental work. As a result, it is confirmed that the thrust and the fuel consumption rate of the engine do not change greatly by varying the exhaust nozzle shape. In the case of the aspect ratio of 5, the specific fuel consumption of the engine is increased by about 3% compared to the reference cone nozzle, but the infrared signal can be reduced by up to 14%. As a result of measuring the temperature distribution of the plume gas, the correlation of infrared signal with plume gas temperature distribution can be understood. In the case of a cone shape, the distribution of plume gas formed to circular shape, and the high-temperature core region of plume gas continued to develop farther to the downstream. However, the temperature distribution was maintained in the rectangular shape as the aspect ratio increased, and the average temperature decreased sharply. As the aspect ratio increases, the plume spreads more widely.


2020 ◽  
pp. 1-21
Author(s):  
Deli Li ◽  
Enlu Wang ◽  
Jinda Mao ◽  
Wei Wu ◽  
Yiyang Wang

Abstract To develop a method of controlling the deposit tube surface temperature, the rules of deposition and fouling on the fireside, and the influence factors of the surface distribution were determined through experiments and theoretical calculations. The surface temperature distribution of a clean tube was compared with that of a deposit tube. Through theoretical calculations, the influence factors of the deposit tube surface temperature were evaluated. Based on the investigation, surface temperature control technology applicable to a super-heater was proposed and the feasibility of this heater was determined. A bimodal distribution was obtained when the temperature distribution of the deposit tube was plotted as a function of the angle, whereas a unimodal distribution was obtained for the clean tube. The results revealed that the heat exchange tube surface temperature is most effectively controlled by controlling the flue gas temperature. Prior to the development of higher performance materials (compared with conventional materials), surface temperature control technology can be used to ensure that the super-heater surface temperature lies below the allowable temperature of existing super-heater materials.


Author(s):  
Z. Wang ◽  
P. T. Ireland ◽  
S. T. Kohler

The gas temperature distribution is important in the measurement and the definition of heat transfer to various gas turbine cooling problems. This paper describes a novel technique which employs encapsulated thermochromic liquid crystals on a fine nylon mesh to give virtually instantaneous gas temperature distribution measurement. The hue value of the liquid crystal on the mesh was calibrated to the gas temperature for a broad response crystal, in the range of 22–40°C, and for a narrow band crystal from 29–31°C. Data processing issues specific to the application of liquid crystals on porous target are discussed and the results of investigations provided. Finally, applications that demonstrate the viability of the method are given.


2016 ◽  
Vol 13 (5) ◽  
pp. 422-431 ◽  
Author(s):  
Chaozhi Cai ◽  
Leyao Fan ◽  
Bingsheng Wu

Purpose This paper aims to understand the outlet temperature distribution of the combustor of a high-temperature, high-speed heat-airflow simulation system. Design/methodology/approach The paper uses numerical simulation to study the temperature distribution of the combustor of a high-temperature, high-speed heat-airflow simulation system. First, the geometrical model of the combustor and the combustion model of the fuel are established. Then, the combustion of fuel in the combustor is simulated by using FLUENT under various conditions. Finally, the results are obtained. Findings The paper found three conclusions: when the actual fuel–gas ratio is equal to the theoretical fuel–gas ratio, the temperature in the combustor of the high-temperature, high-speed heat-airflow simulation system (HTSAS) can reach its highest and the distribution is the most uniform. Although increases in the total temperature of the inlet air can increase the highest temperature in the combustor of the HTSAS, the average temperature of the combustor outlet will decrease. At the same time, it will lead to an uneven temperature distribution of the combustor outlet. When the spray angle of the kerosene droplet is at 30 degrees, the outlet temperature field of the combustor is more uniform. Originality/value The paper presents a method to analyze the combustion performance of fuel and the gas temperature distribution in the combustor. The results will lay the foundation for the gas temperature control of a combustor.


2013 ◽  
Vol 393 ◽  
pp. 741-746 ◽  
Author(s):  
Hasril Hasini ◽  
Norshah Hafeez Shuaib ◽  
Wan Ahmad Fahmi Wan Abdullah

This paper presents CFD analysis of the effect of syngas combustion in a full scale gas turbine combustor with specific emphasis given to the flame and flue gas temperature distribution. A base case solution was first established using conventional natural gas combustion. Actual operating boundary conditions such as swirl, diffusion and fuel mass flow were imposed on the model. The simulation result is validated with the flame temperature of typical natural gas combustion. Result from flow and combustion calculation shows reasonable trend of the swirl mixing effect. The maximum flame temperature was found to be the highest for syngas with the highest H2/CO ratio. However, the flue gas temperature was found to be approximately identical for all cases. The prediction of temperature distribution in the combustor would enable further estimation of pollutant species such as CO2and NOxin complex regions within the combustor.


Author(s):  
T. I-P. Shih ◽  
C.-S. Lee ◽  
K. M. Bryden

The heat-transfer coefficient (HTC) in internal-coolant passages can vary appreciably about a heat-transfer enhancement feature such as a pin fin, a rib, and a concavity because of stagnation regions and wakes about the enhancement feature. However, the computed or measured HTC is often averaged spatially in the spanwise direction or over some region when used in the design of cooling strategies. Since the variation in the HTC could be a factor of eight or more about an enhancement feature, it is of interest to understand the effects of averaging the HTC on the predicted temperature distribution in the solid subjected to the heating and cooling. In this computational study, a flat plate of thickness H (1 mm) and length L = 20H is heated on one side by either a constant heat flux (68 W/cm2) or a constant HTC (1,167.2 W/m2-K) and a constant hot-gas temperature (1,482 °C). On the cooled side, the free stream or bulk temperature is kept constant (400 °C) and the average HTC (1,442.5 W/m2-K) is kept constant as well. This average HTC on the cooled side is the average of a higher HTC (hH) and a lower HTC (hL). Two types of changes from hH to hL are considered — abrupt (or step) and gradual. When the HTC changes abruptly, hH is imposed over LH, and hL is imposed over LL=L–LH. When the HTC changes gradually from hH to hL, hH is imposed from from x = 0 to LH/2, and hL is imposed from x = 3LH/2 to L with a smooth variation in the HTC to connect hH and hL. Results obtained show that when the averaged HTC is used, the maximum temperature in the plate is 900 °C on the heated side of the plate. However, if the variation in the HTC is accounted for, then the maximum temperature in the plate could be as high as 1.363 times the maximum temperature predicted by assuming an averaged HTC. Also, for the range of parameters studied, the difference in the maximum and minimum temperature in the plate can increase by a factor of 16, which strongly affects thermal stress.


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