The present work reports a one-dimensional model to predict the liquid length and spray penetration of diesel sprays when using blends of single-component fuels. A high-pressure liquid-vapour equilibrium has been implemented by means of fugacity coefficients, together with the hypothesis of a real-gas mixture to calculate the partial enthalpy of each component. The model has been validated in a first step by means of an experimental study using binary blends of n-decane and n-hexadecane, where the temporal evolution of the liquid length and vapor spray penetration have been measured. Results show that the model predicts adequately the spray penetration for the different fuels at various conditions. A six-component fuel has also been investigated. Results indicate that this fuel has a very similar evaporative behavior to n-hexadecane, which is confirmed by both experiments and model predictions.