Modeling and numerical simulation of an industrial scale metal hydride reactor based on CFD‐Taguchi combined method

Abstract

This study proposes a cylindrical reactor design embedded with bifurcating longitudinal finned cooling tubes as the heat exchanger for an industrial-scale metal hydride reactor system. We use Taguchi method as an optimization technique for the design parameters. The model performance was simulated with an objective of attaining the least time of absorption. The optimization involved seven control factors in an array of L 18 (2 1 3 6 ). We observed that the number of cooling tubes, the fin length, and the number of fins are the most critical parameters for optimizing absorption time. A three-dimensional numerical model has been developed using COMSOL Multiphysics 5.2a to predict the optimized design's hydriding performance. The absorption characteristics were studied based on the variation of pressure and heat transfer fluid temperature. At a supply pressure of 20 bars and a cooling fluid temperature of 20 C in a 50 kg system with 8 bifurcating finned cooling tubes, a hydrogen storage capacity of 1.21 wt% was achieved in 700 seconds. This paper highlights an optimized design's efficiency and operating parameter's influence to garner the best performance for rapid hydrogen charging.

Design of metal hydride reactor with embedded helical coil using optimization methods

“…In the next step, the objective functions are calculated by experiments or simulation based on the combination of factors level arranged in orthogonal array. The calculated objective function is then used to calculate the signal to noise ratio (SNR) value for each experiment with 'Smaller the better' case defined as [37,38]. The mean SNR value for each control factor level known as performance characteristic (PS) is then calculated using these SNR value.…”

Review of thermal management technology for metal hydride reaction beds

“…7i), 95 bio-inspired leaf-vein type fins, 96 and bifurcated fins (Fig. 7j) 97 are constructed based on the longitudinal structure, and these three structures all have more branches and expand the area in contact with the MHB, and the tree-shaped fins can reduce the hydrogen absorption time by 20.7% among them. The fins are formed into a network structure for more uniform heat transfer.…”

“…Fig. 7 Schematic of (a) inner fins; 82 (b) outer fins; 87 (c) combined inner and outer fins; 88 (d) transverse fins; (e) longitudinal fins; 91 (f) pin fins; 99 (g) conical fins; 92 (h) perforated fins;94 (i) tree-shaped fins; 95 and (j) bifurcated fins 97. …”

Parametric and sensitivity analysis of metal hydride hydrogen storage systems for development of novel design charts

“…The improvement in reaction kinetics is observed by using cooling tubes of different shapes (straight, helical, U‐shaped) 32‐34 . Similarly, the geometrical parameters (width, thickness) and the number of fins of different shapes (transverse, longitudinal, conical, honeycomb structured, branched structured) are also optimized by various researchers 35‐38 . The combination of cooling tubes and fins is also integrated into metal hydride reactors for better heat transfer management 39‐41 …”

“…[32][33][34] Similarly, the geometrical parameters (width, thickness) and the number of fins of different shapes (transverse, longitudinal, conical, honeycomb structured, branched structured) are also optimized by various researchers. [35][36][37][38] The combination of cooling tubes and fins is also integrated into metal hydride reactors for better heat transfer management. [39][40][41] It is observed from the literature that many efforts have been made to improve the heat transfer rate inside the metal hydride bed, which results in faster reaction kinetics.…”