Development of Synthetic Jet Air Blower for Air-breathing PEM Fuel Cell
This paper presents a synthetic jet air blower actuated by PZT for air blowing for air-breathing micro PEM fuel cell. The several factors to affect the performance of air-breathing PEM fuel cell such as air flow rate, opening ratio and cathode open type in the cathode side were studied. Especially, an air flow rate is critical condition to improve its performance. In this paper, we developed a synthetic jet air blower to supply a high stoichiometric air flow. The synthetic jet mechanism is a zero mass flux device that converts electrical energy into the momentum. The synthetic jet actuation is usually generated by a traditional PZT actuator, which consists of a small cylindrical cavity, in/outlet channel and PZT diaphragms. The flow rate of the fabricated synthetic jet air blower was 400cc/min at 550Hz and its power consumption was very low under 0.3W. The proposed air-breathing PEM fuel cell which installed synthetic jet air blower was higher performance and stability during continuous operation than the air-breathing fuel cell without auxiliary device to supply the air. The results showed that the maximum power density was 188mW/cm at 400mA/cm. This maximum power density and durability were improved more than 40% and 20%, respectively. Keywords— Air-breathing PEM fuel cell, Synthetic jet air blower, Opening ratio, Power consumption.
Evaluation of planar free-breathing polymer electrolyte membrane fuel cell design
Abstract A planar cell design for free-breathing fuel cell is studied. The cathode side of the cell was directly open to ambient air in a way that oxygen needed by the fuel cell reaction was provided by diffusion through the cathode side gas diffusion backing, i.e. the cell had no cathode side flow channels. The aim of the study was to demonstrate the feasibility of the cell concept by experimentally evaluating its performance with polarisation and current transient measurements. The orientation of the cell did not significantly affect the performance of the cell and signs of flooding were not observed. The maximum power density achieved in the polarisation measurements was ∼124 mW cm−2. The current transient measurements revealed that with a small base load the cell is capable of producing momentarily current densities up to 500 mA cm−2. The maximum transient power density achieved was ∼194 mW cm−2 at transient current density of 450 mA cm−2. According to the results it seems that this kind of cell design is feasible for small-scale applications, such as portable computers.
Application of Automatic Tracking Correlation Filtering in Motored Spindle Dynamic Balancing
According to the information characteristics of the dynamic imbalance signal and the definition of correlation function,the principles and algorithm of relevant filter with automatic tracking is given.In labview development system,based on the principles of relevant filter with automatic tracking,the graphics programming of extracting the dynamic imbalance signal is developed.With this programming,the vibration signal including different frequency harmonic signals and noise is processed by simulation and on-site experiment.The results show that: through relevant filter with automatic tracking,the dynamic imbalance signal under different rotating speed can be extracted accurately,and it can meet the requirement of motored spindle dynamic balancing measurement.