Design of Gas turbine engines demands for better aerodynamic characteristics, which in turn helps in controlling emissions. The need of an innovative and high precision aerodynamic design changes require a large amount of testing with less product development duration. So the development of an integrated approach for predicting flow in a gas turbine combustor is of cardinal important in the field of gas turbine engines. In the present work, it is aimed at developing an integrated approach for combustor modeling involving rapid prototyping and water tunnel testing to assess the cold flow numerical simulations; the physical model will be subjected to cold flow visualization and parametric studies and CFD analysis to demonstrate its capability for undergoing rigorous cold flow testing. A straight through annular combustors with axial swirler is chosen for the present study because of it has low pressure drop, less weight and used widely in modern day aviation engines. Numerical Analysis has been performed using different tools of ANSYS in its workbench. ICEM is used for meshing, FLUENT for solving and CFD-Post for post-processing. A semi-automatic unstructured tetrahedral grid is generated and then converted to polyhedral mesh in FLUENT in order to save computational time while keeping the Y-plus value is well below 100 for all the walls. Three dimensional RANS equations are solved using k-ɛ models for the Reynolds numbers ranging from 0.64 x 105- 1.5 x 105 based on the annulus diameter. Post processing the results is done in terms of jet penetration, formation of recirculation zone, effective mixing, flow split and pressure drop for different cases. Physical combustor models are fabricated using Rapid prototyping with Poly Lactic Acid material and approximated 2D combustor model is used for capturing important flow patterns using high speed camera in 2D water tunnel, and for pressure measurement in vertical flow water tunnel. From CFD results, mass flow split ups inside the combustor at primary and dilution holes are calculated and achieved the acceptable range as suggested by previous researchers. For the same hole geometry, dilution holes have slightly higher mass flow equals to approx. 12%, which is may be due to the higher jet to annulus mass flow ratio. Qualitative flow visualization study on 2D combustor model using 2D water tunnel facility clearly predicts the important flow patterns such as flow path and recirculation zones, as expected, which match reasonable well with CFD results. It is also found that the percentage of total pressure drop normalized with the inlet total pressure of combustor is within the acceptable range (i.e. less than 10%) in both the virtual and physical cold flow testing of an optimized annular combustor. Printing parameters of Rapid prototyping required for making combustor models suitable for testing in vertical flow water tunnel setup is finalized. The present integrated approach developed using CFD and Rapid prototyping requires less time for combustor design, development and cold flow testing.