The aim of this paper is to in investigate the performance characteristics of counter flow wet cooling towers experimentally by varying air and water temperatures, fins angle, rate of air flow, rate of water flow as well as the evaporation heat transfer, along the height of the tower. The analysis of the theoretical results revealed before that the thermal performance of the cooling tower is sensitive to the degree of saturation of inlet air. Hence, the cooling capacity of the cooling tower increases with decreasing inlet air temperature whereas the overall water temperature fall is curtailed with increasing water to air mass ratio. From the experimental study the efficiency of the cooling tower and cooling tower characteristics are higher in case of low mass flow ratio due to higher contact area of water to air. Because of better contact area between airs to water the drop in performance of the cooling tower is less. The effect of fins angle on the thermal performance of counter flow wet cooling tower was predicted. The experimental study showed that the cooling range, cooling coefficient, , heat load , change in air relative humidity and cooling tower effectiveness increased with increasing fins angles and optimum fins angle obtained from this experimental work was 70 degree, at this angle all cooling tower performance has been calculated were better. While the approach increased with decreasing fins angles, the minimum approach was obtained for 70 degree fins angles and the maximum approach was obtained for 30 degree fins angles.
In this article, an experimental study of the single-pass hybrid (PV/T) collector is conducted in the climatic conditions of Fallujah city, where the experimental results are compared with a previous research to validate the results. The effect of changing the angle of inclination of the hybrid collector (PV/T) and its effect on the electrical power in the range (20°-50°) is studied. The optimum angle of the collector is found to be 30°, which gives a maximum electrical power of 58.8 W at average solar radiation of 734.35 W/m2. In another experimental study with different air flow rates ranged from 0.04 kg/s to 0163 kg/s, where it is found that the maximum electrical power of 57.66 W at an air flow rate of 0.135 kg/s, while the maximum thermal efficiency reaches 33.53% at an air flow of 0.163 kg/s at average solar radiation of 786 W/m2.
An experimental study was done on a solar water heater which consists of two prisms of orthogonal triangle cross-section with a 210 liters capacity . The heater was easy to make and has a low cost when comparted with other types of solar water heaters that it usually the collector separate on the water store. The study included experimental investigations , the experimental investigation was done under the Iraqi environmental conditions at Baghdad for the period in summer and winter seasons in 2006 but the calculation for only two days 15/7/2006 and 6/12/2006 . The study included testing the heater with & without loading and it tested in 13/12/2006and14/12/2006. draining hot water from storage tank at different rates . The experimental result show the ability to get hot water at 46oC at December i.e. a temperature rise at 30oC with 16oC initial temperature .
In this article, an experimental study of the single-pass hybrid (PV/T) collector is conducted in the climatic conditions of Fallujah city, where the experimental results are compared with a previous research to validate the results. The effect of changing the angle of inclination of the hybrid collector (PV/T) and its effect on the electrical power in the range (20°-50°) is studied. The optimum angle of the collector is found to be 30°, which gives a maximum electrical power of 58.8 W at average solar radiation of 734.35 W/m2. In another experimental study with different air flow rates ranged from 0.04 kg/s to 0163 kg/s, where it is found that the maximum electrical power of 57.66 W at an air flow rate of 0.135 kg/s, while the maximum thermal efficiency reaches 33.53% at an air flow of 0.163 kg/s at average solar radiation of 786 W/m2.
The object of this paper was determined the thermal behavior of present and future constructs Iraqi walls at Baghdad climate region (Latitude 33.2 °N) with or without (40) mm insulating materials. The study was carried out at day (21) July for East Orientation. The obtained results were tabulated in terms of over all heat transfer coefficient, weight of the wall per unit area, wall thickness, temperature difference between outside and inside wall face and the temperature difference between inside of the room and it's inside wall surface through on. day hours and it's average values.
The aim of the study is to investigate the effects oils vegetable blends on the performance of single cylinder compression ignition Engine. The three types of vegetable oil appeared to affect the engine performance in a similar way and compared well with diesel fuel, this paper included prepared four samples fuels . They include (10% sunflower oil- 90% diesel blends) , (10% olive oil – 90% diesel blends), (10% corn oil- 90% diesel blends) and pure diesel . The testing achieved between different fuel simples by using the engine four stroke type (TD111) with a single-cylinder and compression ratio (21:1) . The results show that there is decreasing in parameters performance of engine with using vegetable fuel blends , the brake power decrease as (7.4% ),(5.2%) and ( 1.3%) with using the samples (10% olive oil – 90% diesel blends) , (10% sunflower oil- 90% diesel blends) , and (10% corn oil- 90%diesel blends) respectively compared with pure diesel fuel for the engine speed of 2000 r.p.m. .While at same engine speed the ηbth showed a decrease as (10.9 %),(7.5%) and ( 5.8%) with using the (10% olive oil – 90%diesel blends) , (10% sunflower oil- 90%diesel blends) , and (10% corn oil- 90%diesel blends) respectively compared with pure diesel fuel . At the same time , it can be found that bsfc also increases as (7.9% ) , (5.7%) and ( 2.4%) with using (10% olive oil – 90% diesel blends) , (10% sunflower oil- 90% diesel blends) , and (10% corn oil- 90% diesel blends)compared to pure diesel fuel . The exhaust gas temperature decrease as ( 7 0C),( 5 0C)& (3 0C) with using the samples (10% olive oil – 90% diesel blends) , (10% sunflower oil- 90% diesel blends) , and (10% corn oil- 90%diesel blends) respectively compared with pure diesel fuel for the engine speed of 2000 r.p.m. .
A solar water heating system has been fabricated and tested to analyze the thermal performance of Parabolic Trough Solar Collector (PTSC) using twisted tape insert inside absorber tube with twisted ratio about TR=y/w=1.33. The performance of PTSC system was evaluated by using three main important indicators: water outlet temperature (Tout), useful energy and thermal efficiency (ηth) under the effect of mass flow rate (ṁ) ranges between 0.02 and 0.04 Kg/s with the corresponding of Reynolds number (Re) range (2000 to 4000). In a parallel, a fuzzy-logic model was proposed to predict the thermal efficiency (ηth) and Nusselt number (Nu) of PTSC depending on the experimental results. The fuzzy model consists of five input and two output parameters. The input parameters include: solar intensity (I), receiver temperature (Tr), water inlet temperature (Tin), water outlet temperature (Tout) and water mass flow ( ) while, the output include the thermal efficiency (ηth) and Nu. The final results indicate that, owing to the mixture of the swirling flow of the perforated twisted-tape insert, the perforated twist tape insert enhances the heat transfer characteristics and the thermal efficiency of the PTSC system. More specifically, the use of perforate twist tape inserts enhanced the thermal efficiency by 4% to 4.5% higher than smooth absorber tube. Also, the predicted values were found to be in close agreement with the experimental counterparts with accuracy of ~92 %. So, the suggested Fuzzy model system would have high validity and precision in forecasting the success of a PTSC system compared to that of the traditional model. Pace, versatility, and the use of expert knowledge for estimation relative to those of the traditional model are the advantages of this approach
An experimental study is carried out to compare the thermal performance of a sintered powder metal wick heat pipe. Pure water and absolute ethanol are used as two different working fluids. The pipe is made of copper with 300 mm length, 14 mm diameter, and 1.0 mm wall thickness. The wick is made of copper powder. All the experiments are accomplished and the heat pipe is at the horizontal position (è=0o). The heat flux changed within the range (2.8 -13.13) kW/m2, while all other conditions remained constant. The results show that the thermal performance of the heat pipe is better when water is the working fluid, where the operating temperature and the thermal resistance of the heat pipe are lower when the water is the working fluid.
The aerodynamic characteristics of forward swept wing were studied theoretically and experimentally .In the present work, theoretically a computer program was constructed to predict the pressure distribution about surface of the wing using three dimensional Low Order Subsonic Panel method. The aerodynamic coefficients of the wing were calculated from the pressure distribution which gained from tangential velocities Experimentally ,test were carried out by designing and manufacturing a wing model with special arrangement for pressure tapping, suitable for low wind tunnel testing. The entire wing was rotated rotate about an axis in the plane of symmetry and normal to the chord to produce different sweep and incidence angles for wing, by using rotating mechanism. Wind tunnel test was carried out at (Uپ‡=33.23m/s) for different swept angles and angles of attack.Comparisons were made between the predicted and experimental results. It is good and gave reasonable closeness. It was clear from the present investigation that the lift and drag characteristics for the forward swept wing are less in values compared with the swept back wing, therefore a forward swept wing can fly at higher speed corresponding to a pressure distribution associated for lower speed.
The reducing of heat gain through the outer walls of the buildings in summer will contribute in reducing the air conditioning costs. This is one of the best features of design requirements nowadays. To achieve this, the phase change materials (PCM) can be used as an embedded material in the walls to reduce heat transfer. The paraffin wax is one of the common materials used as a PCM in the building walls. The paraffin wax is used in this study with (20%) volume percentage in the external layer of the treated wall. In the present work, the treated wall (with embedded wax in the wall) and non-treated walls have been experimentally investigated. Two Iraqi wall models were employed to run the experiments, whereby these models were exposed to an external heat source using (1000 W) projector for each model. The temperatures were recorded at different locations in the walls during the charging and discharging periods. The results showed that the temperature of the internal surface for the treated wall was lower than that of the non-treated wall at the end of the discharging period (6 hr) where the temperature difference between the treated and non-treated walls was reached (1.6℃).
An experimental study is achieved to study the thermal performance of forced unglazed solar air collector supplied with perforated absorber flat plate. The study is carried under Iraqi circumferences in Al-Ramadi city .The collector is inclined (90o) on horizontal for the simplicity of setting such type of collector on the wall building and minimize its weight. The measurement is recorded on Winter season for two sunny days and two cloudy days in (January 2012). The results show that its possible to use this type of collectors for heating in Winter time because the maximum out air temperature reach to (34oC) when ambient air temperature at (17oC) in sunny days. A good agreement is shown with the published studies Finally its obtained a good effectiveness for perforated flat plate absorber with high system efficiency.