Extensive experimental and numerical studies of the planar jet impingement concept used in gas-cooled T-tube divertor modules have been previously performed at Georgia Tech.1 The experiments were used to validate the numerical CFD model based on the FLUENT[registered] software package. However, the test module used in those experiments did not duplicate the exact geometry of the T-tube divertor, particularly the single-sided nature of the incident heat flux. In this paper, the thermal performance of a prototypical T-tube divertor module is experimentally and numerically examined. The test module has been designed and constructed to match the geometry, dimensions, material properties, and single-sided heating configuration of the actual T-tube divertor. Experiments were performed using air as the coolant with different values of the incident heat flux. The coolant flow rate and inlet pressure were selected to span the expected range of non-dimensional parameters for the actual helium-cooled T-tube divertor design. The experimental values of the local heat transfer coefficient and pressure drop show good agreement with the numerical (FLUENT[registered] 6.3) predictions. The data obtained in this investigation provide added confidence in the predicted performance of the T-tube divertor concept, and the ability of the FLUENT CFD software package to predict its thermal performance, as well as the thermal performance of other complex gas-cooled high heat flux components.