CFD modeling of the development of thermoconvection currents on the processes of starting low-temperature thermoacoustic engines

Abstract

The energy independence problem of Ukraine is an urgent modern problem. Despite the full-scale war, Ukraine has managed to maintain a stable natural gas production level. According to data from Ukrainian energy companies and relevant ministries, the average gas production amounted to approximately 19 billion m³. Ukraine's own production is sufficient to supply domestic consumers and generate thermal energy, but in the post-war period, there will be problems with supplying industry. This problem can be partially solved by steam conversion of associated gas into synthesis gas by using the waste heat of exhaust gases from gas turbine engines of power modules. The feasibility of using the steam reforming method is substantiated for this purpose. This article presents the results of work on increasing the efficiency and compactness of the elements of such modules for the existing power range of 5000...32000 kW of serial gas turbine engines manufactured by Joint Stock Company “Gas Turbine Research & Production Complex “Zorya”-“Mashproekt” (Mykolaiv, Ukraine). Based on the results of mathematical modeling in the Aspen Plus system, the possibility of obtaining synthesis gas in an amount of up to 0.17 kg/s per 1 MW of engine power of the mobile energy module has been proven. The steam reforming process requires the presence of a large amount of saturated steam for its implementation. Thus, the most dimensional element of such units is the waste heat recovery boiler. Options for intensifying heat transfer processes using heat transfer surfaces made of round pipes with spiral-ribbon finning and round pipes with spiral-ribbon finning with dimpled systems on the fins as elements are considered to reduce the overall dimensions of boilers. The implementation of dimpled systems on the ribs reduces aerodynamic resistance, thereby increasing the surface’s overall thermal-hydraulic efficiency. Using mathematical modeling methods, it has been obtained that the possible reduction in the surface area of waste heat recovery boilers is up to 32% due to the use of dimple systems on flat-finned elliptical cross-section tubes to intensify heat transfer.