Saif Watheq Mohammed Ali Al-Turaihi

High-fidelity large eddy simulations (LES) were conducted to characterize the spatial and temporal structure of turbulent flows in an industrial-sized Francis turbine. The unit operated at 50% and 40% of the best efficiency design flowrate. Contours of vorticity, velocity, pressure, and iso-surfaces of Q-Criterion were presented to characterize the effects on the draft tube. Probes placed alongside the draft tube measure the pressure signal to investigate the flow-induced pressure fluctuations inside the turbine unit. The maximum intensity of pressure fluctuations at 50% partial load was 22.66% of the turbine head, while the strength of the pressure fluctuations was 26.36% at 40% partial load. A large number of unorganized smaller vortices observed in the draft tube contribute to the creation of pressure fluctuations. Two pressure modes can be easily recognized (1) high frequency with low amplitude pressure fluctuations and (2) low frequency with high amplitude fluctuations. These pressure fluctuations could be harmful to the structural integrity of the unit and also have undesirable influences on the operational stability of the hydro-turbines.

A water-energy nexus analysis for a Natural Gas Combined Cycle power plant equipped with Post- Combustion Carbon Capture unit was studied. Once-through and hybrid indirect dry and wet cooling systems were considered. An optimization model was developed to minimize the water requirement in each of the cooling system. The model and numerical method were validated with previously reported experimental measurements. In once-through cooling system, the optimized mass flow rates were slightly less than the original operating condition. For hybrid cooling system, the effects of air to water ratio, humidity content, air wet bulb temperature, and the number of cycles of concentration on the water requirements were studied for a wide range of cooling load split factors. The difference in water requirement becomes insignificant when the cooling load exceeds 60%. It was shown that the increase in the number of cycles of concentrations reduces water losses within 5–6 cycles. It is recommended to consider dynamic control for the cooling system using the developed optimization algorithm to maintain optimum operating conditions. For the once-through cooling system, maintaining the least water withdrawal while protecting aquatic life is suggested. For hybrid cooling systems, keeping the split factor below 0.5 and optimizing water consumption and power penalty are recommended.

Integrating solar assisted plant with a carbon capture unit to provide the required reboiler heat duty has been recently investigated extensively to reduce the negative impact of carbon capture unit on plant performance. However, using solar assisted plant to provide the required energy in the reboiler of the stripper leads to increase plant's condenser duty unfavorably. In the present study, two novel configurations have been proposed for a concentrated solar assisted power plant to generate the required reboiler duty in the stripper of a post-combustion carbon capture unit (PCCC-SAPP) in a (630 MWe) natural gas combined cycle (NGCC) power plant to reduce both the condenser duty and power penalty of the plant simultaneously. In the present study, both the solar plant and plant's low-pressure steam (LPS) are contributing to deliver the required reboiler thermal energy in the first method while the extraction is from the cooling system load in addition to the solar plant in the second method. Solar contribution factor (SCF) is the main criteria which has been used to evaluate the findings. Condenser duty with its associated water requirements, power penalty, and the required solar field land area are the parameters which have been investigated in the preset study. It has been found that the second configuration method has better impact on the performance of the plant and its associated cooling system than the first configuration method where zero power penalty is consumed in the second configuration as well as reducing the condenser duty with its related water usage amounts. In addition, it was shown that raw water withdrawal and consumption amounts in term of (gal/min)/MWnet decrease with increasing SCF in the first configuration where raw water withdrawal and consumption amounts are 7.23 (gal/min)/MWnet, and 5.17 (gal/min)/MWnet at SCF equals to 0 while these amounts reach to 6.74 (gal/min)/MWnet and 4.82 (gal/min)/MWnet at SCF of 0.95 respectively. On the other hand, these amounts increase with increasing SCF in the second configuration where water withdrawal and consumption values approach 6.75 (gal/min)/MWnet, and 4.92 (gal/min)/MWnet at SCF equals to 0 while the amounts are equal to 7.93 (gal/min)/MWnet and 5.81 (gal/min)/MWnet at SCF equals to 0.95 respectively despite that condenser duty is increasing in the both methods. This comes from the fact that the net produced power is increasing in the first scenario with SCF while it keeps constant in the second scenario. Furthermore, the relationship between the solar field's required land area and solar direct normal irradiation (DNI) was investigated in the present paper under four different SCF; 0.2, 0.4, 0.6, and 0.8. It was found that reducing the solar field's required land area requires increase in the DNI and decrease in the SCF where the reboiler heat duty is constant in the PCCC and the relationship is almost exponential. The validation was performed with an American governmental report (NETL, 2015) showing that the presented results has a significant agreement with the report.

Electric power generation from thermoelectric power plants is associated with a negative impact on water availability, referenced as the water‐energy nexus, which is aggravated by climate change. In the present study, the effect of four different hybrid cooling system configurations on water usage and power penalty of a natural gas combined cycle has been investigated. The hybrid cooling system with a parallel connected indirect dry cooling system and wet cooling system is the most conventional studied hybrid cooling system in the literature, while the other studied hybrid configurations in the present study are novel regarding their effect on water requirement and power penalty. Simulations were conducted using the COCO 3.3 software and have been validated using data sets from a reference natural gas combined cycle plant, both with and without carbon capture unit, which is available in the literature. Four hybrid cooling system configurations were explored to evaluate their water requirements and power penalty. Other conventional cooling systems such as closed cooling, once‐through, and direct and indirect dry cooling methods were simulated with and without postcombustion carbon capture (PCCC) integration for comparison. It was found that the hybrid configuration, including indirect air‐cooled condenser and natural draft wet cooling tower, has the best performance as compared to the other conventional and hybrid cooling systems, amounting to 2.038 (gal/min)/MWnet, 1.573 (gal/min)/MWnet, and 12.29 MW for water withdrawal, consumption, and energy penalty, respectively, for the case of a unit without PCCC unit and 3.9 (gal/min)/MWnet, 2.928 (gal/min)/MWnet, and 15.177 MW for water withdrawal, consumption, and energy penalty, respectively, for a unit with carbon capture unit. It was confirmed that the PCCC integration approximately doubles the water withdrawal and consumption for all cooling systems. In addition, the indirect air‐cooled condenser and wet cooling tower is still the best performing cooling system with PCCC integration.

Abstract Heat transfer process and fluid flow in a solar chimney used for natural ventilation are investigated numerically and experimentally her in. Solar chimney was designed, manufactured and tested by selecting different positions of air entrance namely: bottom entrance, side entrance, and both side and bottom entrances. The effect of integrating the chimney with paraffin (phase change material) on its thermal behavior has been also investigated. CFD analysis based on finite volume method is used to predict the thermal performance, and fluid flow in two-dimensional solar chimney under unsteady state condition, to identify the effect of different parameters such as solar radiation, and inclination angle. Experimental results show that a solar chimney with side entrance gives better thermal performance; also integrating solar chimney with PCM extended the ventilation period after the sunset. A comparison between the numerical and the experimental results shows fair agreement.

Experimental analysis of a thermoelectric generator (TEG) and solar parabolic trough collector (PTC) is described in this paper. The TEG concept was created with the intention of using sun radiation as a source of heat. Stainless steel sheet (SSS) is used to construct the parabolic trough collector as its focused surface. The main component of the thermoelectric generator is the commercial thermoelectric module composed of bismuth telluride (Bi2Te3). The temperature of the cold side of TEG is stabilized by PCM's absorption of heat during melting. The focused solar radiation and the PCM-cooled heat sink provide the driving force behind the production of energy. Numerous operational factors are examined, including the temperature of the cold side, the receiver plate, the PCM's mean temperature, the power output, and the solar radiation. Results shows a maximum temperature of 99.8 °C was achieved with Concentrated solar radiation of 1996.9 W/m2.

In the current research, the static deflection of the pre-twisted beam has been calculated experimentally and numerically using finite element approach (ANSYS workbench 2020R1) and under the effects of different twist angles, different lengths, four boundary conditions of edges support of the beam. The beam was manufactured from PETG filament material by a 3D printer at room temperature. The obtained results showed reasonable acceptance between the experimental and numerical pre-twisted beam deflection. The numerical maximum deflection of the pre-twisted beam decreased with the increase of twisted angle of the beam for clamped-simply and simply-simply edges support. While it was irregularly various for clamped-clamped edge support with a minimum value of the maximum deflection occurred at the twist angle 135o. The maximum deflection of the pre-twisted beam is disappeared gradually at the twist angles greater than 270o for claimed-free edge support. In addition, the maximum deflection of the pre-twisted beam increased due to the beam length increment.

Wind energy becomes one of the promised solutions as alternatives of using fossil power energy in the upcoming decades. As pressure fluctuation and flow deficit in the near wake play a crucial role in predicting the turbine performance, the novelty in the current study focuses on a three dimensional (3 D) transient numerical simulation to investigate near wake characteristics of NREL phase IV wind turbine. Pressure fluctuation spectrum and wake deficit at four sections downstream the turbine are the main parameters studied as well as the flow streams and iso-surface characteristics. The mentioned parameters are studied at four sections: (0.25 D), (0.5 D), (0.75 D), and (1 D) of turbine diameter. The obtained results are compared with corresponding data from the NREL Phase IV experiments for validation purposes. Results show that the highest-pressure fluctuation spectrum would be at the nearest wake region, and, then it decreases periodically. Hub pressure spectrum density is much lower than that density for the turbine blade. The wake deficit profile shows that the deficit is developing with time at a rate equal to (0.115 rate per sec). In addition, it was found that the wake is recovered just (1 d) of the hub diameter while the blade wake deficit becomes the dominant after (0.75 D) of turbine diameter to cover the whole wake region. It was also found that the downstream distances should be extended more to resolve the whole wake recovery. The comparison with the tests measurements shows agreement between both the numerical and experimental works such that the error doesn't pass 4.3 %.

Functioning with providing alternative energy sources, finding new fuel mixtures, and diminishing the environmental and economic risks of combustion have become some of the most important challenges nowadays round world. Fuel type and composition significantly affect flame characteristics, which represent essential considerations for designing any combustion system. The current experimental study aims to investigate the characteristics and height of the premixed LPG flames with CO2 dilution. The investigation included testing four equivalence ratios (0.8, 1, 1.2, & 1.4), four CO2 dilution ratios (0%, 5%, 7.5%, & 10%). The un-burnt mixture flow rate varies between flame flashback and blowout limits in each case. It has been noticed that the equivalence ratio dominates flame height and flame aspect ratio for all mixture types and compositions at all operating conditions. The flame of LPG elongates from 35.8 mm to 56.5 mm when increasing the equivalence ratio from 1 to 1.4. The flow rate of the fuel/air mixture affects the flame height and flame aspect ratio positively. The addition of CO2 as a diluent gas elongates the flame, especially when increasing the equivalence ratio and/or flow rate since there is more than one influence, they all agree on the same effect on flame height. The flame stability limits expand with increasing the equivalence ratio and improve due to CO2 addition. The LPG-CO2/air mixture shows a better response to overcome flame flashback.

Recently, most oil companies are working to reduce the cost and carbon emissions accompanied crude oil distillation process by developing suitable sustainable technologies. The present work studies the viability of retrofitting concentrated solar collector (CSC) represented by parabolic trough collector (PTC) through the crude oil distillation process in three stages; crude oil preheating in a furnace, live steam injection, and the reboiler heater. The whole oil distillation unit and the PTC unit are modeled and solved using an American software called COCO V 3.6.0.13 and SAM 2022.11.21 (System Advisor Model). Three different working fluids are investigated through the study: therminol VP-1, hitech solar salt, and pressurized water at different mass flow rates. Additionally, the proposed system was analyzed economically using levelized cost of energy (LCOE) method. The required land area for the solar unit is analyzed through the study too. It was found that hitec solar salt requires higher input flow rate than the other heat transfer fluids (HTF) where the maximum flow rate reaches about (75 kg/s) while the minimum flow rate was found for pressurized water as the flow rate value reaches about (25.7 kg/s). It was found also that the maximum required thermal energy is the energy exhausted in the furnace for crude oil preheating process, and the minimum value is the energy required for steam generation. The economic feasibility study shows that retrofitting such a solar units would be more beneficial in the years period between 2022-2050 as the LCOE of flue gas (0.0363 $/kWh) is higher than the LCOE of PTC (0.01604 $/kWh) leading to an overall cost saving reaches about 14523013 $ after year of 2021. The land area analysis shows that the required area is increasing linearly in a rate of (0.62 kW/m2). The validation with recorded data from literature shows a good agreement in compare with the current work.

Solar- (Thermoelectric Generator) TEG hybrid system has recently become the most widely studied and developed system. This paper focuses on the creation of solar-TEG hybrid systems and thoroughly assesses recent developments in solar-TEG hybrid energy technology. The study investigates the integration of concentrated solar thermal systems and photovoltaic (PV) cells with thermoelectric generators (TEGs). Studies on hybrid systems integrating concentrated solar units with TEG units have demonstrated encouraging outcomes in increasing energy conversion efficiency. Furthermore, it has been noted that phase change materials (PCM) and appropriate cooling systems are crucial for optimizing the performance of concentrated solar collector (CSC)-TEG or CSC-PVT-TEG systems. The potential of concentrated solar power (CSP) technology in areas with high solar irradiation is also covered in the study, focusing on the significance of connectivity opportunities and efficient energy generation. The current study considered the most recent development in solarTEG hybrid systems, the results highlight how important new ideas and cuttingedge technology are to expanding the field of solar energy use for sustainable energy solutions

INTERNATIONAL CONFERENCE ON RECENT INNOVATIONS IN (ENGINEERING (ICRIE 202

Saif attended number of workshops which have been developed by ASHRE in Georgia/ Atlanta for three days

Attending the MIT Energy Efficiency Conference from April/03/2019 till April/05/2019

Attending Combustion course in Princeton University in the USA from June/24/2019 till June/30/2019