The Measurement of Thermal Performance for a Fluidized Bed

Abstract Experiments have been performed to measure the thermal performance, packed density, and velocity of a fluidized bed cooling tower of 280 mm diameter. Hollow plastic spheres of three different sizes, with diameters of 20, 25 and 37 mm and particle densities ranging from 70 to 325 kg/m3 were investigated as packing materials, and results for static bed heights of 100 mm and 300 mm are reported. Measurements were obtained at an approximately constant inlet hot water temperature of around 42°C and cover a range of water mass flux from 0.3 to 3.6 kg/sm2. Liquid/gas ratios varied between 0.1 and 5.5. Results for thermal performance are presented showing the effects on the cooling tower characteristic, KaV/L, of the different packing elements and of varying water flow rate, air flow rate and the height of the hot water distributor above the bed. This provides a useful semi experimental relation, in the area generally lacking in design and performance data

Combined effect of the magnetic field, orientation, and filling ratio on cylindrical pulsating heat pipe using distilled water and distilled water/Fe3O4 nanofluid

To investigate the effect of the magnetic field, a pulsating heat pipe was made in the shape of a cylinder and Fe3O4 nanoparticles (%0.1 wt) were used with the base fluid of distilled water as the working fluid. (Tetramethyl ammonium hydroxide) TMAH surfactant was used as a stabilizer. To investigate the effect of gravity on the performance of the pipe, the device was tested at different angles from zero to 90 degrees. In this research, the effect of different variables, including the type of working fluid (distilled water vs. nanofluid), filling ratio, slope, and amount of heat input to the evaporator (30–300 W), in two different states, once without the influence of the magnetic field and once again with the application of a magnetic field was investigated. The results of the tests showed that the performance of the device at 50 % filling ratio is better than 60 % filling ratio. The use of nanoparticles improved the performance of the device. Inclining the device increases the thermal resistance so that the device performs poorly in the horizontal mode in all modes except when it is under the influence of a magnetic field. The use of nanofluid, as well as the application of a magnetic field, makes the start-up time of the device decrease by 37 % and 30 %, respectively, compared to distilled water. The temperature of the start of fluctuations also decreases by 24 % and 32 %, respectively