In this paper the heating process in a box annealing unit is simulated and the effect of various parameters involved in the process is examined. For this purpose, the full Naiver-Stokes equations along with the standard k- turbulence model are solved in the fluid region using the finite volume approach. In the solid area the conduction heat transfer equation is employed using approporate surfac...

Aero gas turbine engines have been using mainly film cooling and convection cooling techniques. For operating at high gas temperature amongst different cooling options the transpiration cooling technique has emerged as the most promising technique to improve the gas turbine cycle performance by allowing higher turbine inlet temperatures. This paper investigates the advantages of transpiration c...

In this Simulation, supersonic combustion of hydrogen at Mach 3.12 has been presented. The combustor has a single fuel injection perpendicular to the main flow from the base. Finite rate chemistry model with K-ε model have been used for modeling of supersonic combustion. The pressure rise due to the combustion is not very high on account of global equivalence ratio being quite low. Within the i...

This paper illustrates the mechanism of U-shaped vortex formation which is found both by experiment and DNS. The main goal of this paper is to explain how the U-shaped vortex is formed and further develops. According to the results obtained by our direct numerical simulation with high order accuracy, the U-shaped vortex is part of the coherent vortex structure and is actually the tertiary strea...

The rarefied flow of nitrogen with speed ratio ͑mean speed over most probable speed͒ of S =2,5,10, pressure of 10.132 kPa into rectangular nanochannels with height of 100, 500, and 1000 nm is investigated using a three-dimensional, unstructured, direct simulation Monte Carlo method. The parametric computational investigation considers rarefaction effects with Knudsen number Kn= 0.481, 0.962, 4.81...

Aggressive fuel burn and carbon dioxide emission reduction goals for future gas turbine engines will require higher overall pressure ratio, and a significant increase in turbine inlet temperature. These goals can be achieved by increasing temperature capability of turbine engine hot section materials and decreasing weight of fan section of the engine. NASA is currently developing several advanc...

Forced convective condensation in vertical channel is investigated numerically. The condensation boundary layers that occur due to temperature difference between the walls and saturation temperature of steam is simulated by the volume of fluid (VOF) method. The effect of variations in the hydraulic diameter, steam velocity, Re number and temperature difference between the wall and saturation te...

Improving the performance and durability of gas turbine aircraft engines depends highly on achieving a better understanding of the flow interactions between the combustor and turbine sections. The flow exiting the combustor is very complex and it is characterized primarily by elevated turbulence and large variations in temperature and pressure. The heat transfer and aerodynamic losses that occu...

In order to compare the performance of the carbon dioxide and HFC-125 heat pumps for medium-and high-temperature heating, both heat pump cycles were optimized using a simulation method. To fairly compare the performance of the cycles by using different working fluids, each cycle was optimized from the viewpoint of heating COP by two design parameters. The first is the gas cooler exit temperatur...

The off-design performance of a combined cycle gas turbine (CCGT) plant for power generation is of great importance. In this work, a detailed mathematical model is developed for a triple-pressure reheat combined cycle power plant. Using the model, CCGT off-design operation and efficiency are studied under four gas turbine (GT) strategies. Controlling the turbine inlet temperature (TIT) gives be...