Lean-burn combustion is one of the key technologies which can contribute to the reduction of future aero-engine emissions. Two principle candidate designs are currently proposed for lean-burn combustion systems, of which lean direct injection (LDI) combustion may emerge as the future mainstream lean-combustion technology. For low emission LDI combustion, the design of the fuel injector is crucial. This work therefore aimed at establishing design rules for future LDI combustion systems and, LDI injectors in particular. A novel low TRL multi-sector water flow facility has been developed. This three-injector facility introduced more aerodynamically representative boundary conditions to a water flow environment, thus increasing flow fidelity. In addition, the test facility has been designed to allow a variable injector pitch spacing. Three spacings could be realised. A stereo PIV system has subsequently been integrated to measure the flow. The modular design of the facility furthermore offers ample opportunity for future low TRL LDI combustion system research. This work identified a recirculation of injector jet fluid which previously has been misinterpreted as an injector jet distortion under the influence of the liner flow. It was also shown that, in a multi-sector environment, a non-uniformity in the distribution of circumferential velocity is established, increasing with a decreasing injector spacing. This non-uniformity was demonstrated to govern the fuel droplet distribution described in previous work. This work could further demonstrate a distortion of the emerging injector jet, issuing into the downstream injector liner. Depending on the injector spacing, the distortion was quantified at 10.44%, relative to an undistorted single injector test case. The contribution of the diffuser inlet to this distortion was estimated at 14.8%. It could also be shown that this distortion is not affecting the injector jet uniformly, but is a localised effect. In addition, it could be shown that in a three-injector environment, no significant aerodynamic difference exists between plenum and diffuser fed injectors. Injector feed non-uniformities, previously ascribed to a mismatch in size between injector and diffuser, could be attributed to the effect imposed by the multi-sector environment.