It is found in many film-cooling experiments and computational analyses that a heated surface is employed to simulate the actual film-cooling condition with a cooling jet and a hot main flow. Considering that the dominant energy passage in turbine airfoil film cooling is always from the hot combustion gas flowing into the airfoil, employing a heated surface to simulate the actual film cooling c...

In recent years, in order to reducing die design and manufacturing costs, Multi point forming technique has gained an increasing interest because of its high flexibility. In this process, the conventional fixed shape solid die sets are replaced with a pair of opposite matrices of controllable elements. In this paper, the fundamental principles of multi-point forming was described and the possib...

In this paper, the loading path was optimized in hot metal gas forming (HMGF) process for making AA6063 cylindrical stepped tubes. For purpose, response surface method (RSM) and finite element (FEM) were applied using Design-Expert ABAQUS softwares, respectively. The parameters of internal pressure, pressure rate, axial feeding, punch speed examined based on central-composite design three level...

the incremental sheet metal forming (ismf) process is a new and flexible method that is well suited for small batch production or prototyping. this paper studies the use of the finite element method in the incremental forming process of aa1050 sheets to investigate the influence of tool diameter, vertical step size, and friction coefficient on forming force, spring-back, and thickness distribut...

Introduction Coal gasification produces residual particles of coal char, coal ash, and sorbent that are suspended in the fuel gas stream exiting the gasifier. In most cases, these particles (referred to, hereafter, simply as char) must be removed from the stream prior to sending the gas to a turbine, fuel cell, or other downstream device. Currently, the most common approach to cleaning the gas ...

In the absence of H2 molecules, the primordial gas in early dark matter halos with virial temperatures just above Tvir > ∼ 10K cools by collisional excitation of atomic H. Although it cools efficiently, this gas remains relatively hot, at a temperature near T ∼ 8000 K, and consequently might be able to avoid fragmentation and collapse directly into a supermassive black hole (SMBH). In order for...

We present an overview of some of the issues surrounding current models of galaxy formation, highlighting recent insights obtained from cosmological hydrodynamic simulations. Detailed examination of gas accretion processes show a hot mode of gas cooling from near the halo’s virial temperature, and a previously underappreciated cold mode where gas flows in along filaments on dynamical timescales...

How galaxies form from, and are fueled by, gas from the intergalactic medium (IGM) remains one of the major unsolved problems in galaxy formation. While the classical Cold Dark Matter paradigm posits galaxies forming from cooling virialized gas, recent theory and numerical simulations have highlighted the importance of cold accretion flows—relatively cool (T ∼ few × 104 K) unshocked gas streami...