KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Subject: search.filters.subject.Film cooling

Search Results

Now showing 1 - 4 of 4
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Numerical Solutions of Heat Convection Problems in Film Cooling Flow Over Adiabatic and Diabatic Flat Plates
    (2026-03-06)
    Jeatrakul, Karn
    ;
    Prapamonthon, Prasert
    ;
    Wongsatanawarid, Atikorn
    ;
    Wang, Yeteng
    ;
    Hao, Zhanzhou
    This paper presents numerical solutions for film cooling flow over a flat plate subjected to heat convection problems, namely (1) adiabatic, and (2) diabatic plates with constant heat fluxes of 500 and 1000 W/m<sup>2</sup>. The governing equations and realizable k-ε turbulence model are solved to provide numerical solutions in terms of film effectiveness for the adiabatic case, and dimensionless temperature and Nusselt number for the diabatic case. Numerical solutions are carried out at two film hole angles i.e. α = 25° and 35° and two blowing ratios i.e. BR = 0.3 and 0.6. The numerical solutions indicate that the smaller angle and lower blowing ratio can provide better effective cooling on the flat plate for both problem conditions. In addition, the strong influence of the blowing ratio on the film cooling flow is observed. When the heat flux is included, the Nusselt number increases in spanwise and streamwise direction with the heat flux.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    NUMERICAL PREDICTION OF THERMOMECHANICAL SENSITIVITY OF THE FIRST STAGE NOZZLE GUIDE VANE WITH FILM COOLING
    (2022-01-01)
    Khumhaeng, Siwanart
    ;
    Suksa, Thitapa
    ;
    Laohalertchai, Nutcha
    ;
    Chaiprasit, Benyapa
    ;
    Chotroongruang, Thanapat
    Practically, a gas-turbine engine's first-stage nozzle guide vane (NGV) must operate under extreme conditions induced by high temperatures from burned gases, causing severe damage to the vane, such as cracks or fatigue failures. As a result, the first stage NGV's lifespan is shortened. In other words, the first stage NGV's lifespan is determined by the vane material's durability. Therefore, effective cooling systems and thermal barrier coating (TBC) are provided. This paper presents a numerical prediction of the thermomechanical sensitivity of the first stage NGV with film cooling under aerothermal conditions and TBC using a 3D CFD/CHT approach with a static structure model for a steady temperature analysis. Turbine inlet temperature (TIT), coolant inlet temperature (CIT), blowing ratio (BR), and TBC thickness, which are key factors for gas turbines' performance improvement, are used as independent variables. An examination of vane cooling performance is presented in the first part, followed by a prediction of the thermomechanical sensitivity of the vane under the four variables in terms of von Mises equivalent stress and strain in the second part. The findings obtained from both parts show that the relationship between cooling performance and thermomechanical characteristics is sensitive to the influences of turbine inlet temperature (TIT), coolant inlet temperature, and TBC thickness. In addition, the findings indicate the role of the blowing ratio in thermal and mechanical sensitivity for the filmcooled vane.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Understanding of temperature and cooling effectiveness sensitivity of a film-cooled vane under coolant inlet temperature effect: A case study
    (2019-09-01)
    Prapamonthon, Prasert
    ;
    Yin, Bo
    ;
    Yang, Guowei
    ;
    Zhang, Mohan
    This work presents a case study of the relationship between temperature and cooling effectiveness of a film-cooled vane under effect of coolant inlet temperature in two aspects based on the actual and base coolant inlet temperatures. Results are conducted in terms of temperature, cooling effectiveness, and heat transfer coefficient based on surface and volume analyses using CFD/CHT approach. Sensitivity of the vane temperature and cooling effectiveness under this effect is discussed also. The results show that for the surface basis, although the cooling effectiveness obtained from the actual coolant inlet temperature is quite straightforward and follows the definition of the cooling effectiveness directly, the cooling effectiveness obtained from the base coolant inlet temperature is more understandable because it corresponds to the variation of the surface temperature. Based on the volume basis and the base coolant inlet temperature, the 8% increase in the coolant inlet temperature causes the reduction of the average and maximum cooling effectiveness, which corresponds to 18 K and 25 K increments in the average and minimum temperatures, respectively. However, when the actual coolant inlet temperature is used, the variation of the cooling effectiveness is rather insensitive due to the reduction of heat flux on the hot-side wall.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    CHT/CFD analysis of thermal sensitivity of a transonic film-cooled guide vane
    (2019-01-01)
    Prapamonthon, Prasert
    ;
    Yooyen, Soemsak
    ;
    Sleesongsom, Suwin
    Thermal parameters are important variables that have great influence on life time of turbine vanes. Therefore, accurate prediction of the thermal parameters is essential. In this study, a numerical approach for conjugate heat transfer (CHT) and computational fluid dynamics (CFD) is used to investigate thermal sensitivity of a transonic guide vane which is fully film-cooled by 199 film holes. Thermal barrier coating (TBC), i.e., the typical TBC and a new one as the candidate TBC, and turbulence intensity (Tu), i.e., Tu=3.3%, 10% and 20%, are two variables used for the present study. At first the external surface temperatures of the vane material are compared. Next, the TBC surface temperatures are considered. Results show the major role of the lower thermal conductivity of TBC which results in the lower and more uniform temperature on the external surface of the vane substrate. Finally, the thermal sensitivity is presented in terms of the percentage reduction of the external surface temperatures of the vane material and the structural temperatures of the vane material at midspan, including the variations of average and maximum vane temperatures. Results show that TBC and Tu have significant effects on the external surface and structural temperatures of the vane substrate. The lower thermal conductivity of TBC leads to the higher difference between the thermal conductivity of the vane substrate and TBC, the reduction of heat transfer and the more uniform temperature within the vane structure. The results also show more effective protection for the average vane temperature from the two TBCs at higher Tus. However, Tu does not significantly affect the reduction of the maximum vane temperature even though the new TBC, which has the very low thermal conductivity, is used.