https://reports.aerade.cranfield.ac.uk:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. 2026-04-19T18:53:57Z https://reports.aerade.cranfield.ac.uk/handle/1826.2/4872 The influence of flow parameters on minimum ignition energy and quenching distance Experiments have been carried out on the effects of pressure, velocity, mixture strength, turbulence intensity and turbulence scale on minimum ignition energy and quenching distance. Tests were conducted at room temperature in a specially designed closedcircuit tunnel in which a fan was used to drive propane/air mixtures at subatmospheric pressures through a 9 cm square working section at velocities up to 50 m/s. Perforated plates located at the upstream end of the working section provided near-isotropic turbulence in the ignition zone ranging from 1 to 22 percent in intensity, with values of turbulence scale up to 0.8 cm. Ignition was effected using capacitance sparks whose energy and duration could be varied independently. https://reports.aerade.cranfield.ac.uk/handle/1826.2/4871 Note on Wind-Tunnel Measurements of Yawing Moment, Rudder Fixed and Free, on Models of Three Aircraft Adamson, J E; Brown, E C; Allen, R H 1941-07-01T00:00:00Z https://reports.aerade.cranfield.ac.uk/handle/1826.2/4870 The Equations of Hydrodynamics in a Very General Form Cope, W F 1942-11-01T00:00:00Z https://reports.aerade.cranfield.ac.uk/handle/1826.2/4869 The design of wind tunnel fans. Collar, A. R. Summary.—The present report is one of a series dealing with N.P.L. methods for the design of return flow wind tunnels. Reports already issued deal with the design of the Compressed Air Tunnel¹ and Open Jet Tunnels,² with the design of corner cascades³ and fan straighteners, ⁴ and with the improvement of velocity distribution by means of windmills⁵ and gauzes.⁶ An explanation is now given of the method usually adopted in the design of fans for return flow tunnels ; as an example of the method, the design of the fan for the N.P.L. non-turbulent tunnel is considered in detail. It is shown that for a wind tunnel a fan with blades of constant chord is advisable ; and a formula is given by means of which a rapid estimate can be made of the variation in rotational speed of the fan corresponding to a variation in power factor at constant power. 1940-08-10T00:00:00Z