1.Review of the heat flux and the heat transfer coefficient measuring instruments 2.1.Heated sensors 2.2.Slug Calorimeter 2.3.Auxiliary wall-type heat meters 2.4.Thin film gauge - Gardon type 2.5.Review of inverse methods for determination of the heat flux and the heat transfer coefficient 2.5.1.Inverse determination of local heat transfer coefficient 2.5.2.Inverse method for the heat flux determination in the boiler water-walls 2.5.3.Current application of the IHCP in the heat flux determination in various branches of industry 3.Aim and scope of the work 4.Description of the proposed method 4.1.Finite volume method 4.2.Inverse space marching method 4.3.Smoothing input temperature data 5.Testing of the method 5.1.Description of the industrial case - control rod CFD simulation results 5.2.Verification of testing results 6.Measuring instrument design 6.1.Measuring instrument with grooves 6.2.Measuring instrument with openings 6.3.Thermocouples calibration and verification 6.4.Verification of thermocouples location 7.Testing stand 7.1.Testing and measurement results 7.2.Heat flux measuring errors 8.Application of the Finite Volume-Finite Element Method 8.1.FEFVM formulation for the direct and the inverse heat conduction problem 8.2.Determination of temperature distribution in the direct region 8.3.Determination of temperature distribution in the inverse region 8.4.Method validation 8.5.Application using real measurement data 8.6.Validation of the results 9.Flowmeter for measuring a low mass flow rate of liquids 9.1.Analytical model 9.2.Numerical model of the flowmeter 9.3.Thermal flowmeter and test stand