Hussain H. Al-Kayiem

Simulation of solar chimney power plant with an external heat source

Solar chimney power plant is a sustainable source of power production. The key parameter to increase the system power output is to increase its size but the plant cannot operate during night hours. This study deals with simulation work to validate results of pilot plant at Manzanares and include the effects of waste heat from a gas turbine power plant in the system. The effects show continuous night operation, a 38.8 percent increase in power at 1000 W/m2 global solar irradiation at daytime and 1.14 percent increase in overall efficiency.

Multidimensional minimization training algorithms for steam boiler drum level trip using artificial intelligent monitoring system

This paper deals with the Fault Detection and Diagnosis of steam boiler using developed artificial Neural networks model. Water low level trip of steam boiler is artificially monitored and analyzed in this study, using two different interpretation algorithms. The Broyden-Fletcher-Goldfarb-Shanno quasi-Newton and Levenberg-Marquart are adopted as training algorithms of the developed neural network model. Real site data is captured from a coal-fired thermal power plant in Perak state - Malaysia. Among three power units in the plant, the boiler drum data of unit3 was considered. The selection of the relevant variables to train and validate the neural networks is based on the merging between the theoretical base and the operators experience and the procedure is described in the paper. Results are obtained from one hidden layer and two hidden layers neural network structures for both adopted algorithms. Detailed comparisons have been made based on the Root Mean Square Error. The results are demonstrating that the one hidden layer with one neuron using BFGS training algorithm provides the best optimum NN structure

Experimental investigation of the effect of wind speed and wind direction on a solar chimney power plant

Wind has been reported to have adverse effect on the performance of traditional solar chimney power plants but no reference has been made on the wind effect on inclined solar chimneys. An experimental investigation on the effects of ambient wind speed and wind direction on the performance of a south facing inclined solar chimney power plant model is reported in this paper. The effect of ambient wind speed and direction on the system performance was analyzed and the results showed that for the south facing collector, wind speed and directions have strong effects on the plant performance. The wind speed was found to have considerable influence on the convective heat loss through the cover and the walls to the ambient. Considering the wind direction, it was found that the system performance was favoured when the wind direction is from south moving north while the performance is impaired when the wind direction is from east or west. The results also showed some performance degradation when the wind is from the north. The findings also revealed that the walls of the air flow channel of the system resist the wind from sweeping the hot air generated in the system out to the ambient. Based on the findings, the use of inlet guide vanes as wind breakers at the collector inlet of traditional solar chimney power plant can reduce the losses associated to the wind effect inside the collector. The wind breakers will channel the natural energy of the wind into the system and enhance the system performance.

Numerical Simulation of High Frequency Electromagnetic Wave in Microwave Cavity for Soot Oxidation

Soot oxidation temperature by high frequency electromagnetic energy was proposed using numerical simulation by combining electromagnetic with transient thermal analyses. Equation of electric field distribution in a microwave cavity with perfect electric conductor surfaces and TE10 mode is formulated from Helmholtz equation. The dissipated heat distribution is calculated from the electric field distribution. Six study cases for electric field and dissipated heat distributions were implemented by using ANSYS software based on finite element method. The impact of dielectric sample properties, position, size and shape inside the microwave cavity were predicted. The results from the simulation of electric field and dissipated heat were compared with available data in literature and showed the validity of the analysis. It was found that the electric field forming hot spots at penetration depth and front corners of the soot sample and penetration depth is equal to 12mm but equal to 0 for samples with dimensions less than penetration depth. Dissipated heat pattern depend on electric field pattern and dielectric properties.

Optimizing electro-thermo Helds for soot oxidation using microwave heating and metal

Soot is produced by incomplete combustion of various carbon-containing compounds. Soot is one of the main environmental pollutants and has become an important environmental and specific objective. To reduce soot from exhaust emission of diesel engine, a new technique is proposed and implemented by using metal inserted in the soot exposed to electromagnetic radiation. This paper presents a simulation to obtain optimum metal length and shape that give optimum electric field for attaining temperature enough for soot oxidation using microwave heating and a thin metal rod. Four cases were numerically examined to investigate the electric field and temperature distributions in a mono-mode TE10 microwave cavity having closed surfaces of perfect electric conductors. The operating frequency is 2.45 GHz, and power supply is 1500 W. The simulation methodology is coupling the absorbed electromagnetic energy with heat transfer energy. The absorbed electromagnetic energy is found from the electric field within the soot. The simulation was run using ANSYS based on finite element method. The results of the four simulation cases show that the optimum simulation is represented by case 2 where the value of electric field is 39000 V/m and heating time to arrive at the oxidation temperature (873 K) is 35 s using cylindrical metal rod of 8 mm length. It is revealed that the concept of achieving high temperature for soot oxidation by using thin metal rod inside a microwave cavity can be applied.

Numerical Simulation of Microwave Heating for Soot Oxidation

This paper presents the simulation of microwave heating by coupling high frequency electromagnetic with transient heat transfer using finite element method edge base of ANSYS software. Helmholtz equation of electric field has been formulated from Maxwell equations to predict electric field and the mathematical model of transient thermal analysis was included. Three cases have been examined numerically to investigate electric field, dissipated heat, temperature distribution and weight loss of soot at operation frequency 2.45 GHz. The simulation results showed that heat is generated from inside to outside of soot. The temperature at penetration depth increased till ignition point and after further heating, maximum temperature was attained, followed by temperature decreases due to mass transport. Maximum electric field was found to be located on the front face for the small samples with dimensions less than penetration depth. The predicted results have been compared with experimental results which show the validity of the simulation.

Simulation of incident solar power input to fixed target of central receiver system in Malaysia

This paper presents the design procedure of 3 dual-axis heliostat units located in Ipoh, Malaysia (latitude 4.34°N). Hourly sun position during day was estimated using a mathematical model that has been developed to calculate the cosine efficiency distribution for heliostat field layout design. The final layout of the heliostat field is designed by varying the tower height and the ground distance of the concerned heliostats and then evaluating the cosine efficiency of the heliostat field in terms of feasibility and workability due to land, material, and cost limitations. The total incident solar power to a fixed target on the tower was simulated for an entire year using TRNSYS software. The simulation outputs indicate that the heliostat field delivers 7.58 kW as peak value in December 28th where the total reflective area is 9 m2. The design specifications shall be used to build a solar power tower testing facility and the simulation results are required to approximate the power input to the receiver system for sizing purpose in the future.

Coupled Analytical-Numerical Procedure to Solve the Double Wedge Spiked Supersonic Intake Flow Field

Designers of the aero engines are in quest of maintaining the pressure as high as possible at the face of the compressor, with air velocity not higher than 0.8 Mach. Reduction of the flow from supersonic to such speed is combined with pressure reduction. This paper presents results from coupled techniques to solve for the flow field of double wedge spiked supersonic intake. The selected spike has 4° forebody wedge angle and the second ramp angle is 8°. The external part of the flow was solved analytically while the internal part was solved numerically by finite volume technique. The analysis was carried out at different Mach numbers (1.4, 1.8, 2.2, 2.4, and 3) and different angles of attack (0°, 6°, and 12°). The procedure is validated and the results are presented in terms of the pressure recovery at the face of the compressor. The results have shown that generally the pressure recovery decreases by increasing of incidence angle. The non-zero incidence was found to produce noticeable difference in pressure distribution at the face of the compressor. This became considerably effective at incidences leading to detached shocks at the leading edge of the spike.

Data acquisition and control system for on-line measurement and analysis of complex flow fields

The accurate measurements in complicated flow fields like the reversal and wake flows are representing a challenge for the fluid dynamics researchers. The present paper deals with the description of a developed flying X-hot-wire probe / computer interfacing technique which enables detailed turbulence evaluation within reversal and wake flows. The probe attacks the flow and sweeps within the flow field with a velocity higher than the reversal flow velocity. The signals at 19 pre-selected points (per sweep) in the flow field are transferred to a minicomputer for on-line data acquisition and analysis. The main components of the system are the flying hot wire mechanism, motor control unit, interfacing unit and a minicomputer. The electronic components and their programming and functioning are described in details in this paper. The validity tests of the developed system are presented and discussed. The results showed that the system is capable to measure the 2-D velocity components in mean velocity of around 5 m/s within an error limit of ± 0.9%. For higher mean velocity, of 19.7 m/s, the system measures the two velocity components with an error limit of ± 0.57%. Within such limits of errors, the system is verified for measurement in complex flows with good accuracy.

Multidimensional minimization training algorithms for steam boiler high temperature superheater trip using artificial intelligence monitoring system

Steam Boilers are important equipment in power plants and the boiler trips may lead to the entire plant shutdown. To maintain performance in normal and safe operation conditions, detecting of the possible boiler trips in critical time is crucial. As a potential solution to these problems, an artificial intelligent monitoring system specialized in boiler high temperature superheater trip has been developed in the present paper. The Broyden Fletcher Goldfarb Shanno Quasi-Newton (BFGS Quasi Newton) and Levenberg-Marquardt (LM) have been adopted as training algorithms for the developed system. Real site data was captured from MNJ coal-fired thermal power plant-Malaysia. Among three power units in the plant, the boiler high temperature superheater of unit one was considered. An integrated plant data preparation framework for boiler high temperature superheater trip with related operational variables, have been proposed for the training and validation of the developed system. Both one-hidden-layer and two-hidden-layers network architectures are explored using neural network with trial and error approach. The obtained results were analyzed based on the Root Mean Square Error for developed intelligent monitoring system.