Numerical Investigations of the Combined Effects of Flow Rate and Methanol Concentration on DMFC Performance

Abstract

Abstract:A modified 3D numerical model on the energy conversion process in the anode side of a Direct Methanol Fuel Cell (DMFC) system was constructed and validated to published experimental results. Systematic simulations were performed to investigate the underlying mechanisms of the energy conversion process, and the combined effects of inlet flow rate and input methanol concentration were summarized systematically. The increase of flow rate was found to be an effective strategy to accelerate the internal flow fields, while the diffusion layer was proposed to be a critical component in the design of high-performance DMFC. The frontier for optimal conditions of DMFC's output was also determined, which can be helpful to improve the energy conversion performance of DMFC in practical applications.

An Adaptive Operation Strategy for Voltage Stability Enhancement in DMFCs

“…A three-dimensional numerical model was developed and validated to experimental results in our previous studies [22,23]. It was designed by integrating the governing equations of continuity, momentum conservation, species transport and electrochemical phenomena.…”

“…It was designed by integrating the governing equations of continuity, momentum conservation, species transport and electrochemical phenomena. It has been successfully applied to investigate the energy conversion process in a DMFC system [23], which is just the same one as that we used in the present study. Therefore, this well-developed numerical model is adopted in the present study to investigate the underlying mechanisms of the adaptive operation strategy.…”

“…For simplicity and concision, more details about the numerical model were not contained here, which can be available in Ref. [22,23]. in unoptimized experimental process, for which the operating conditions are summarized in Table 3.…”

“…Simulations were carried out using the proposed 3D numerical model [23]. The operating conditions were chosen to be the same as that for Fig.…”

“…Many published experimental results have shown that the output voltage could be very sensitive to a small variation of current density [2,5,6,7]. Although a voltage stabilizer can be system [23]. Although the effects of operating conditions, such as temperature, methanol concentration and solution/air flow rates, on the DMFC performance can be well estimated using those existing models [24,25], an adaptive operation strategy that optimally controls the operating conditions can still be necessary for the enhancement of voltage stability in practical applications.…”