This study focuses on fires in road tunnels in order to increase the level of security for users. This paper proposed numerical investigations carried out on a small scale tunnel model to study the fire-induced smoke CONTROL by longitudinal and longitudinal-natural ventilation systems. We studied the effect of two ventilation systems on the temperature distribution and stratification of the pollutant to estimate the effectiveness of ventilation systems. The FLOW is characterized by the temperature fields, temperature profiles and the Froude number. The numerical tool used is FDS (version 4.0). This numerical study requires validation with experiment and numerical results and comparison with the model developed by Kunsch J.P. to evaluate the critical velocity. However, good agreement with experimental results, it confirms the possibility of using this code in the problem.

Modeling of generalized unified power FLOW CONTROLler (GUPFC), based on the static consideration, and has been presented in this paper used for power FLOW CONTROL.A Newton-Raphson load FLOW program has been developed which includes comprehensive CONTROL facilities and yet exhibits very strong convergence characteristics. The injection model, which is used to locate GUPFC suitably in the power system, is incorporated into an existing Newton-Raphson load FLOW algorithm in polar coordinate. The modified Jacobian matrix and power mismatch equations are deduced based on the injection model of GUPFC to CONTROL active and reactive powers and voltage magnitude in any combination or to CONTROL none of them. Test results are presented on IEEE 30- bus system, which demonstrate the effectiveness of the proposed method.

In this paper the power FLOW CONTROL at power systems in the presence of distributed generation is analyzed. The work proposes use of Unified power FLOW CONTROLler (UPFC) to CONTROL the power FLOW at the load bus by Main supply in coordination with DG source. This work shows that using UPFC leads to the reduction of the oscillation power and voltage at the time of three phase fault in the system. The studies are performed based on the well known software, MATLAB/SIMULINK Simulation results show that the stability and effectiveness of the applied operation of DG source in coordination with the main utility can be achieved by using UPFC.

The aim of this work is to CONTROL the FLOW around ground vehicles by active or/and passive strategies. The active CONTROL is achieved by steady, pulsed or closed-loop jets located at the back of the simplified car model. The passive CONTROL is performed using porous layers between the solid body and the fluid in order to modify the shear forces. The two previous CONTROL methods can be coupled to improve the drag reduction.

We consider a grid network where nodes contain small buffers. A packet that faces a crowded buffer in its route will get extra latency and may be dropped. In this paper, we propose a novel FLOW CONTROL protocol called RFCC for grid networks. RFCC tries to reroute delayed packets and utilizes network coding to introduce a configurable amount of redundant information in the network, thereby increasing reliability in the face of packet loss. RFCC contains a number of mechanisms to adapt to the traffic model on a grid interconnection network in a multiprocessor system. Our simulation experiments show that RFCC improves reliability with comparable traffic overhead compared to the case in which RFCC is not used.

In the present paper, an experimental and numerical investigation of fluid FLOW and heat transfer in the case of wall injection besides main FLOW through a circular sudden enlargement are studied. The injected FLOW is achieved through an annular slot placed around the inner side wall of the step. The static pressure variation along the sudden enlargement length is measured and calculated at different values of injection ratio (Q) and injection FLOW angles. The average heat transfer with Reynolds number (ReJ) of injected FLOW at different values of the inlet FLOW angle is obtained. The velocity, turbulent kinetic energy and temperature contours are presented in this study. Reynolds number of injected FLOW is varied between 320 and 840, Reynolds number of main FLOW is between 5895 and 8450 and the injection FLOW angles are 0o, 15o, 30o, 45o and 60o. In the injection case, the results indicate that, the pressure recovery coefficient increases by decreasing the injection ratio and increasing the FLOW angle. The average heat transfer coefficient increases as both injection Reynolds number and the injection FLOW angle increase. The numerical results showed that two recirculation zones generate behind the step between the injection FLOW and the main FLOW. The size of these recirculation zones decreases by increasing the injection FLOW rate. The turbulent kinetic energy increases within region between the recirculation zones and main zone also, it decays by injecting FLOW in the recirculation zone. The length for higher value of FLOW temperature decreases by injecting FLOW in the recirculation zone, and that length increases as the injection FLOW rate increases. The comparison between the experimental results and the numerical results gives good agreement using the k-e model with Leschziner and Rodi correction.

This paper proposes a Flexible Power Electronic Transformer (FPET) for the application in the micro-grids. The low frequency transformer is usually used at the Point of Common Coupling (PCC) to connect the low voltage grid and utility network to each other. The conventional 50Hz transformer results in enhanced low voltage-grid power management system during grid-connected operation. In this paper, the whole system represented as two, three-phase AC systems with an intermediate high-frequency transformer for power FLOW CONTROLling. The FPET consists of a high frequency transformer and three-phase to single-phase matrix converter. The matrix converters are modulated with a Pulse Width Modulation (PWM) strategy for a bi-directional power FLOW CONTROL. Phase shift modulation strategy in two sides of FPET is used for power FLOW CONTROLling by PI CONTROLler from utility network to low voltage grid and vice versa. FPET model is established in Matlab/Simulink software with CONTROLler for power FLOW CONTROLling. Presented simulation results have shown the validity of the proposed CONTROL system for FPET through the Matlab/Simulink simulation.

One of the important ways of improving axial compressor performance is to CONTROL the tip leakage FLOW near the endwall region. Numerical computations were conducted to investigate the impact of blade tip suction on the axial compressor cascade performance in current paper. Three suction schemes located on the blade tip with different chordwise coverage were investigated in total. The results show that the cascade overall performance can be effectively enhanced by the proper suction scheme on the blade tip and the best scheme should be arranged at slightly downstream of the onset point of the tip leakage vortex (TLV). The CONTROL effectiveness and mechanisms are different for the different suction schemes. For the suction scheme covering the starting point of TLV, the onset point of TLV is shifted downstream, while an additional induced leakage FLOW near the blade leading edge is generated resulting in the increase of mixing loss. It is more effective when the structure of the main TLV is destroyed and divided into different parts by applying the blade tip suction arranged slightly behind the onset point of TLV. In addition, the blade loading is redistributed near the blade tip after the blade tip suction and the total pressure loss caused by the suction slots should also be considered in the design process.

In this paper, an unsteady two-equation model that describes the FLOW of water in unsaturated zones is developed. The governing equations are based on general conservation laws of mass and momentum. Although the obtained governing equations are not amenable to being solved by analytical means, a CONTROL volume numerical solution using upwind scheme can be sought. In order to test the model equations, two test examples of one- and two-dimensional water infiltration are simulated. The effects of discretization on spatial and temporal coordinates are demonstrated. Also, the results are compared with the results of previous studies.

This article reports the active CONTROL of base FLOWs using the experimental procedure. Active CONTROL of base pressure helps in reducing the base drag in aerodynamic devices having suddenly expanded FLOWs. Active CONTROL in the form of microjets having 0. 5 mm radius placed at forty-five degrees apart is employed to CONTROL the base pressure. The Mach numbers of the present analysis are 1. 7, 2. 3, and 2. 7. The length to diameter (L/D) ratio is varied from 10 to 1 and the nozzle pressure ratio (NPR) being changed from 1 to 10 in steps of 1 for base pressure measurements. The area ratio for the entire analysis is fixed at 2. 56. Wall pressure distribution along the enlarged duct is also recorded. No change in base pressure increase/decrease is thoroughly analysed as well. From the experimental investigation, it is found that CONTROL plays an important in modifying the base pressure without disturbing the wall pressure distribution. The base pressure variation is entirely different at L/D = 1 compared to a higher L/D ratio due to change in reattachment length and the requirement of the duct length at higher inertia levels. The quality of the FLOW in the duct in the presence and absence of CONTROL remained the same.