Radially resolved measurement of stator heat transfer in a rotor–stator disc system

The scale up of a rotor-stator spinning disc reactor by stacking single stage rotorstator units in series is demonstrated. The gas-liquid mass transfer per stage is equal to the mass transfer in a single stage spinning disc reactor. The pressure drop per stage increases with increasing rotational disc speed and liquid flow rate. The pressure drop is more than a factor 2 higher for gas-liquid flow than for liquid flow only, and is up to 0.64 bar at 459 rad s À1 . The high mass and heat transfer coefficients in the (multistage) rotor-stator spinning disc reactor make it especially suitable for reactions with dangerous reactants, highly exothermic reactions and reactions where selectivity issues can be solved by high mass transfer rates. Additionally, the multistage rotor-stator spinning disc reactor mimics plug flow behavior, which is beneficial for most processes.

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“…16,17 . This is up to an order of magnitude higher than in conventional reactors, such as stirred tanks, bubble columns, and packed bed reactors.…”

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confidence: 99%

Multistage rotor‐stator spinning disc reactor

2011

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“…All the tested correlations available in the literature have proven to be unsuitable. The objective of this research is to obtain reliable and accurate models to calculate the heat transfer coefficient needed for the further design of the optimal cooling system of a hightemperature PEMFC stack that will be incorporated to the powerplant of a light UAV capable of reaching an altitude of 10,000 m. To this end, the energy supply technique [12,13] has been applied in experiments performed in two rectangular tunnels, for three different form factors, in conditions similar to those expected for the HT-PEMFC stack. For calculations, convective and radiative processes are considered.…”

Section: Latin Alphabetmentioning

confidence: 99%

“…An example of this method is the determination of the surface temperature analyzing the emitted radiation intensity and wavelength using infrared cameras [10,11]. A direct heat transfer measurement method is the energy supply technique, in which the temperature of a solid surface is measured while actively providing heat [12,13]. Other methods for the direct measurement of the heat transfer coefficient are the use of thin film heat flux sensors [14e16] or the one based on naphthalene sublimation that has been used to measure the convective heat transfer coefficient on the horizontal roof of a real building [17].…”

Section: Introductionmentioning

confidence: 99%

Experimental determination of the heat transfer coefficient for the optimal design of the cooling system of a PEM fuel cell placed inside the fuselage of an UAV

Barroso

Renau

Lozano

et al. 2015

Applied Thermal Engineering

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h i g h l i g h t sHeat transfer coefficients to refrigerate a HT-PEMFC stack are calculated. Experiments are performed in 2 wind tunnels, for 3 form factors and real conditions. The calculated heat transfer coefficient varies from 8 to 44 W m À2 K À1 . Results at sea level are suitably extrapolated for a target altitude of 10 km. Flow area is optimized as a function of the power required to cool the stack down. a b s t r a c tThe objective of this research is to calculate the heat transfer coefficients needed for the further design of the optimal cooling system of a high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) stack that will be incorporated to the powerplant of a light unmanned aerial vehicle (UAV) capable of reaching an altitude of 10,000 m. Experiments are performed in two rectangular tunnels, for three different form factors, in experimental conditions as close as possible to the actual ones in the HT-PEMFC stack. For the calculations, all the relevant thermal processes are considered (i.e., convection and radiation). Different parameters are measured, such as air mass flow rate, inlet and outlet air temperatures, and wall temperatures for bipolar plates and endplates. Different numerical models are fitted revealing the influence of the diverse relevant non-dimensional groups on the Nusselt number. Heat transfer coefficients calculated for the air cooling flow vary from 8 to 44 W m À2 K À1 . Results obtained at sea level are extrapolated for a flight ceiling of 10 km. The flow section is optimized as a function of the power required to cool the stack down to the temperature recommended by the membrane-electrode assembly (MEA) manufacturer using a numerical code specifically developed for this purpose.

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“…The resultant uncertainty of the open load loss is derived from the first-order approximation of the total error arising from product of torque and rotation speed. The details of the uncertainty analysis will not be presented here but is discussed in [12]. The uncertainty for this set of open load loss measurement has a maximum value of 7.7%.…”

Section: Experimental Measurementmentioning

confidence: 99%