An efficient finite element analysis/computational fluid dynamics (FEA/CFD) thermal coupling technique has been developed and demonstrated. The is achieved by an iterative procedure between FEA CFD calculations. Communication calculations ensures continuity of temperature heat flux. In the procedure, simulation treated as unsteady for a given transient cycle. To speed up coupling, steady are employed, considering that flow time scales much shorter than those solid conduction therefore...

Flow and heat transfer in an aero-engine compressor disk cavity with radial inflow has been studied using computational fluid dynamics (CFD), large eddy simulation (LES), coupled fluid/solid modeling. Standalone CFD investigations were conducted a set of popular turbulence models along 0.2 deg axisymmetric 22.5 discrete sector models. The overall agreement between the predictions is good, solutions are comparable to established integral method solution major part cavity. LES demonstrates...

The buoyancy-affected flow in rotating disk cavities, such as occurs compressor stacks, is known to be complex and difficult predict. In the present work, large eddy simulation (LES) unsteady Reynolds-averaged Navier-Stokes (RANS) solutions are compared other workers’ measurements from an engine representative test rig. Smagorinsky-Lilly model was employed LES simulations, RNG k-ε turbulence used RANS modeling. Three cases were investigated a range of Grashof number Gr=1.87 7.41×108 buoyancy...

Use of computational fluid dynamics (CFD) to model the complex, 3D disk cavity flow and heat transfer in conjunction with an industrial finite element analysis (FEA) turbine thermomechanical response during a full transient cycle is demonstrated. The FEA CFD solutions were coupled using previously proposed efficient coupling procedure. This iterates between calculations at each time step solution ensure consistency temperature flux on appropriate component surfaces. 2D representation high...

In compressor inter-disc cavities with a central axial throughflow it is known that the flow and heat transfer strongly affected by buoyancy in centrifugal force field. As step towards developing CFD methods for such flows, buoyancy-driven flows under gravity closed cube sealed rotating annulus have been studied. Numerical simulations are compared experimental results of Kirkpatrick Bohn (1986) et al (1993). Two different codes used shown to agree stationary problem. Unsteady show good...

Abstract Flow and heat transfer in axial compressor disk cavities involve strong interaction of throughflow at the bores with centrifugal buoyant flow cavities. This paper presents large eddy simulation (LES) rotating a heated shroud relatively weak cooling throughflow. The conditions considered for single cavity configuration correspond to Rossby numbers Ro=0.2 0.3, rotational Reynolds ReΩ=3.2× 105 7.7×105, buoyancy parameters βΔT=0.24 0.26. Reasonable agreement results measurements was...

The buoyancy-affected flow in rotating disc cavities, such as occurs compressor stacks, is known to be complex and difficult predict. In the present work large eddy simulation (LES) unsteady Reynolds-averaged Navier-Stokes (RANS) solutions are compared with other workers’ measurements from an engine representative test rig. Smagorinsky-Lilly model was employed LES simulations, RNG k-ε turbulence used RANS modelling. Three cases were investigated a range of Grashof number Gr = 1.87 7.41×108...

An efficient finite element analysis/computational fluid dynamics (FEA/CFD) thermal coupling technique has been developed and demonstrated. The is achieved by an iterative procedure between FEA CFD calculations. Communication calculations ensures continuity of temperature heat flux. In the procedure, simulation treated as unsteady for a given transient cycle. To speed up coupling, steady are employed, considering that flow time-scales much shorter than those solid conduction therefore...

Abstract Code_Saturne, an open-source computational fluid dynamics (CFD) code, has been applied to a range of problems related turbomachinery internal air systems. These include closed rotor–stator disk cavity, co-rotating cavity with radial outflow and axial throughflow. Unsteady Reynolds-averaged Navier–Stokes (RANS) simulations large eddy (LES) are compared experimental data previous direct numerical simulation LES results. The results demonstrate Code_Saturne's capabilities for...

During asymmetric faults in power grid, the negative-sequence modulation voltage decomposed by three-phase isolated cascaded H-bridge photovoltaic grid-connected inverter will redistribute active powers, which may cause backflow problem, that is, output of one phase to be less than zero. The dc-bus voltages pump up, triggering overvoltage protection and shutting down from grid. Although existing methods effectively address single-phase two-phase short-circuit faults, there is still larger...

Reynolds-Averaged Navier-Stokes (RANS) computations have been conducted to investigate the flow and heat transfer between two co-rotating discs with an axial throughflow of cooling air a radial bleed introduced from shroud. The computational fluid dynamics (CFD) models coupled thermal model test rig, predicted metal temperature compared thermocouple data. CFD solutions are shown vary buoyancy driven regime forced convection regime, depending on inflow rate prescribed at At high rate, show...

Flow and heat transfer in an aero-engine compressor disc cavity with radial inflow has been studied using computational fluid dynamics (CFD), large eddy simulation (LES) coupled fluid/solid modelling. Standalone CFD investigations were conducted a set of popular turbulence models along 0.2° axisymmetric 22.5° discrete sector models. The overall agreement between the predictions is good, solutions are comparable to established integral method solution major part cavity. LES demonstrates that...

At present, the grid connection guidelines require large and medium-sized photovoltaic (PV) power stations to have certain low voltage ride through (LVRT) capability, that is, inverter should actively support in case of failure. However, three-phase isolated cascaded H-bridge (CHB) PV uses DC-DC converter with unidirectional energy flow, so active return problem cannot be avoided. During asymmetric fault, returned will accumulate at DC side capacitor, capacitor pump up, eventually causing...

A wall-modelled large-eddy simulation (WMLES) method previously validated against laboratory experiments is applied to a real engine disc cavity geometry with surface and air temperatures representative of maximum power conditions. An appropriate set independent nondimensional parameters describing the problem defined sensitivities these are investigated by independently varying each parameter in WMLES. Effects change temperature distribution reduction radius downstream also investigated....

Active power backflow is a unique problem of three-phase isolated cascaded H-bridge (CHB) PV inverter during asymmetric grid voltage fault, resulting in the continuous rise dc-bus voltages and that will be eventually shut down off-grid due to out control. The existing methods are able completely suppress active single-phase short-circuit fault two-phase but fails large operating zone when interphase occurs. For this issue, article proposes novel multiple specific harmonic injection method...

Abstract A transient simulation of shutdown cooling for a gas turbine test rig configuration under ventilated natural convection has been successfully demonstrated using coupled aero-thermal approach. Large eddy (LES) and finite element analysis (FEA) were employed fluid domain computational dynamics (CFD) solid component thermal conduction simulation, respectively. Coupling between LES FEA was achieved through plugin communicator. The buoyancy-induced chimney effect the axially is correctly...

Abstract A transient simulation of shutdown cooling for a gas turbine test rig configuration under ventilated natural convection has been successfully demonstrated using coupled aerothermal approach. Large eddy (LES) and finite element analysis (FEA) were employed fluid domain computational dynamics (CFD) solid component thermal conduction simulation, respectively. Coupling between LES FEA was achieved through plugin communicator. The buoyancy-induced chimney effect the axially is correctly...

Abstract A systematic CFD investigation was conducted to assess the core zone (CZ) casing heat transfer of a large civil aircraft engine. Three key engine operating conditions, maximum takeoff (MTO), cruise (CRZ) and ground idle (GI) were analyzed. Steady flows assumed. Turbulence simulated using realizable k-epsilon model in conjunction with scalable wall function. Buoyancy effect taken into account. Radiation calculated discrete ordinate (DO) model. It shown that forced convection...

Thermal analysis of a turbine disc through transient test cycle is demonstrated using 3D computational fluid dynamics (CFD) modeling for the cooling flow and finite element (FEA) disc. The case angular sector high pressure (HP) assembly civil jet engine includes details coolant around blade roots. Proprietary FEA CFD solvers are used to simulate metal domains, respectively. Coupling achieved an iterative loop with smooth exchange information between simulations at each time step, ensuring...

The internal gear box (IGB) of an aeroengine represents a severe challenge in computational fluid dynamics (CFD). In the present study, axisymmetric CFD model was assessed to investigate complex air flow IGB. All non-axisymmetric components and geometry features inside box, such as bearings, gears, bolts slots, well radial drive system vent pipes, were simulated using porous media models. Their resistance estimated either by empirical correlations or preparatory studies comparison with...