XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 Tomasz Babul TEMPERATURE OF NiCrBSi POWDER PARTICLES DETONATION SPRAYED – THEORY AND PRACTICE

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 DETONATION THERMAL SPRAY Advantages of the detonation thermal spraying: Low substrate temperature: the heat transferred to the substrate stays very low. The substrate temperature, during spraying, does not exceed 150 o C. The highest velocity up to 1300 m/s. Low 0.3% porosity and high 250 MPa adhesion. Low cost of operation: –consumption of oxygen is only 3~10% of HOVF (20 to 30 l/m), –less electrical energy consumption: very effective electric power consumption - the unit consumes a total of 200 W, –less downtime: the process is very simple to operate and very reliable. There are literally no components that can wear out, similar to Laval nozzle in the HVOF gun. Can be sprayed multi-type powder from low melting point metal to high melting point of ceramics.

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 THERMAL SPRAYING (

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 DETONATION SPRAYING DEVICE Device for detonation spraying ( )

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 The used powder: alloy NiCrBSi granulation of 25÷45 µm chemical composition: –Ni – 70% –Cr – 16% –Si – 4% –B – 4% –Fe – 4% –C – 2 % powder hardness – 700HV The morphology of the NiCrBSi RESEARCH METHODOLOGY

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 To determine the stream velocity as a function of the stream acceleration way, there was used device with replaceable barrels. Barrels with length of 110 mm, 140 mm, 210 mm, 310 mm, 410 mm, 510 mm and 610 mm were used. DETONATION SPRAYING DEVICE

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 Recording and archiving of output signals were performed using a four-channel digital oscilloscope Tektronix TDS type – 460. System for measuring the stream temperature TEMPERATURE MEASURING SYSTEM

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 TEMPERATURE OF THE NiCrBSi POWDER Temperature of the NiCrBSi powder stream as a function of time measured for the barrel length 110 mm Temperature (series of 5 meas.)

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 TEMPERATURE OF THE NiCrBSi POWDER Temperature of the NiCrBSi powder stream as a function of time measured for the barrel length 260 mm Temperature (series of 5 meas.)

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 TEMPERATURE OF THE NiCrBSi POWDER Temperature of the NiCrBSi powder stream as a function of time measured for the barrel length 510 mm Temperature (series of 4 meas.)

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 TEMPERATURE OF THE NiCrBSi POWDER Temperature of the NiCrBSi powder stream as a function of time measured for the barrel length 610 mm Temperature (series of 4 meas.)

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 Temperature changes for a NiCrBSi powder stream as a function of the barrel length TEMPERATURE MEASUREMENTS SUMMARY

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 FEM MODEL The values of physical constants for Ni powder

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 Temperature distributions were calculated by finite element method – FEM, using the COSMOS/M program algorithm. It was assumed that the heat exchange takes place in the material according to the conduction mechanism described by Fourier’s Law relationship: where: T-temperature, t-time, c p -specific heat, r-density, q-heat stream, k i -thermal conductivity with i-direction. The heat transfer between the considered system and the environment takes place in accordance with the convection mechanism where heat stream is expressed by the following equation: where: h c -heat transfer coefficient, T-considered surface temperature, T ∞ -ambient temperature. MODEL ASSUMPTIONS

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 The purpose of this analysis is to examine the impact of model parameters on calculated temperature value at the considered system point. As a sensitivity measure was adopted dimensionless index calculated from the following equation: where: T-temperature of the considered point, p i -i-time model parameter. This indicator determines the sensitivity of calculated temperature value at the considered system point for the model parameter change. The value of this indicator equal to unity means, that changing the considered parameter for 100%, the calculated temperature value will change also by 100%. Sensitivity indicator value equal to W=-0.5 means, that increasing the considered parameter for 100%, the calculated temperature value will be reduced by 50%, etc. The results of such indicator calculations can be used to evaluate model parameters that have the most significant impact on the temperature distribution of the analyzed object. u MODEL SENSITIVITY ANALYSIS ON THE TEMPERATURE DISTRIBUTION IN SPHERE =25 um

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 MODEL PARAMETERS As the parameters of the model were adopted: p 1 – sphere diameter, p 2 – heat transfer coefficient, p 3 – specific heat, p 4 – density, p 5 – thermal conductivity, p 6 – outside temperature (ambient temperature), p 7 – initial temperature. By comparing the absolute values of the sensitivity indicator calculated for the temperature at time t=4 ms, the model parameters can be arranged by decreasing impact as follows:

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 On the sphere surface: –p 6 – outside temperature (ambient temperature), –p 2 – heat transfer coefficient, –p 3 – specific heat, –p 4 – density, –p 1 – sphere diameter, –p 5 – thermal conductivity, –p 7 – initial temperature. MODEL PARAMETERS

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 Inside the sphere: –p 6 – outside temperature (ambient temperature), –p 1 – sphere diameter, –p 3 – specific heat, –p 4 – density, –p 2 – heat transfer coefficient, –p 5 – thermal conductivity, –p 7 – initial temperature. MODEL PARAMETERS

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 EFFECT OF HEAT TRANSFER COEFFICIENT Effect of heat transfer coefficient on the value of temperature calculation on the surface of a sphere (Ni) with a diameter of 45 µm

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 EFFECT OF HEATING TIME Effect of heating time on the value of the calculated temperature on the surface of nickel powder with a diameter of 25 and 45 µm

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 THE TEMPERATURE DISTRIBUTION The temperature distribution along the radius of nickel powder with a diameter of 25 µm after 10, 50, 100, 200, 300 and 400 µs

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 THE TEMPERATURE DISTRIBUTION The temperature distribution along the radius of nickel powder with a diameter of 25 µm after 10, 50, 100, 200, 300 and 400 µs The temperature distribution along the radius of nickel powder with a diameter of 45 µm after 10, 50, 100, 200, 300 and 400 µs

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 PRACTICE AND THEORY COMPARISON

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 Heat Transfer Coefficient 100 W/(m 2 K) PRACTICE AND THEORY COMPARISON

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 Heat Transfer Coefficient 10 W/(m 2 K) Heat Transfer Coefficient 100 W/(m 2 K) PRACTICE AND THEORY COMPARISON

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM 2014 The calculations for the assumed boundary conditions have shown that the particles surface heating depends primarily on the ambient temperature (temperature of the gaseous detonation products) and depends on adopted for the calculations value of heat transfer coefficient. Changing the value of heat transfer from 10 W/(m 2 K) to 100 W/(m 2 K) causes that the calculated theoretical time needed to heat the powder surface extends approximately 6-times, i.e. from about 0.5 ms to over 3.0 ms. It has been shown that in the case of adoption of a constant heat transfer coefficient value for the calculations, the powder granulation (in the range of 25 µm and 45 µm) did not significantly affect on the duration of its surface heating to the detonation products stream temperature. Maximum duration of surface heating to the ambient temperature (temperature of the gaseous detonation products T ∞ =3273 K) is equal about 0.5 ms. It is worth to mention that calculations shows that the powder temperature is almost identical on its surface and inside which indicates the intensive heat transfer from the surface into the material which is characterized by thermal conductivity. Due to the size of the individual powder particles, calculated results seem to be likely especially for smaller diameters. A comparison of the graphs obtained for the experimental measurements and calculations using the FEM method shows their high compatibility. CONCLUSIONS

XII International Symposium on Explosive Production of New Materials: Science, Technology, Business and Innovations, EPNM