<p>Trapped vortex combustor (TVC) is a combustor design that creates swirl in a cavity to mix air and fuel using the geometrical features of the combustor. TVC was tested under various alternative fuels in the literature, and performance enhancement of it still on progress. This paper will investigate the effect of implementation of lateral angle into traverse angled air injectors under realistic idle operation condition of an aeroengine for propane, ammonia and hydrogen to enhance mixing of the air and fuel. Moreover, it will introduce ammonia as an alternative fuel candidate for TVC with the aim to improve all fuel’s mixing efficiency inside the combustor. Air injectors that are 30° transverse angled were also laterally angled for 15°, 30°, and 45° to compare the mixing efficiency, flow behaviour and fuel trajectory. The results showed that mixing efficiency of 45° laterally angled air injector was highest around fuel jets, around 0.24–0.3, whereas this figure is the lowest at the downstream of the cavity with around 0.08. Increasing lateral angle reduces the fuel distribution, results in extra rotation on tangential direction, and increases in turbulent kinetic energy. While fuel trajectory goes upwards as air injectors more laterally angled for ammonia and propane, this was opposite for hydrogen fuel, which suggest that pure hydrogen fuelled application can be used with 45° laterally angled air injector. However, high turbulent areas, and high rotation on tangential direction should be considered for 45° lateral angle because they could produce high temperature locations and combustion instabilities. 15° lateral angled air injectors are most suitable for this application because it shows low mixing efficiency around fuel jets with 0.21–0.28, and high mixing efficiency compared to other fuels at the end of the cavity while presenting well distributed fuel and extra rotation on tangential direction.</p>