Research on gas replacement scheme for household steamers

Achieving rapid oxygen exhaustion in a steam oven can effectively reduce the oxidative loss of nutrients in food ingredients during the cooking process. Based on the theoretical analysis and numerical simulation of traditional gas displacement methods, this paper designs and tests different gas displacement schemes, and finally proposes new air intake devices to realize piston-type gas displacement, thereby achieving the goal of efficient oxygen exhaustion. Compared to mixed gas displacement, piston-type gas displacement can realize the rapid oxygen removal. The condensation of water vapor has a negative impact on the efficiency of gas replacement. After considering the condensation of water vapor, the range of steam inlet velocity for achieving the gas replacement in the piston was derived. The gas replacement performance for four different schemes is compared, and the influence of the water vapor flow rate is investigated. Numerical results show that the time taken for the oxygen content at the oven center decreasing from 18% to 1% is 22.5 s and 22.1 s for scheme (c) and (d), the time consumption is significantly reduced compared to the prototype with 248s time required. The time required for the oxygen content from 18% to 1% decreases and then increase as water vapor flow rate increases. There exists an optimal mass flow rate (0.7 g·s -1 ) that minimizes the time. The energy and water consumption test for scheme (c) and (d) are conducted, and the high gas replacement efficiency is verified. The scheme (d) achieves 54s for the time required for the oxygen content at the center of the cavity to drop from 18% to 1%, and the time consumption is reduced by 78% compared to the prototype. Furthermore, the scheme (c) and (d) demonstrates significant advantages in reducing both energy and water consumption of the steamer, with decreases of more than 15% in both power consumption and water consumption.