Numerical investigation and experimental validation of an infrared measurement approach for surface heat flux distribution using a multi-color-reference

•Measuring heat flux distribution by infrared camera with a multi-color-reference.•Multi-color-reference with multiple emissivity supplies reference info for measurement.•This method can measure the emissivity and heat transfer coefficient concurrently.•Combining the advantage of contact and non-contact measurement.•The novel model has been analyzed and verified by simulation and experiment.