MathConnex mathematical package for calculating the equivalent thermal conductivity of a strip coil

When heating complex metal loads (layered, fibrous, granular), the gas gaps in them increase the temperature difference across the charge section and lead to an increase in the duration of its heating. Optimizing the time of complex loads heating, which helps to reduce fuel consumption and improve the heated metal quality, requires knowledge of temperature fields in them, which, in turn, depend on the equivalent thermal conductivity of the complex load. For their calculations mathematical modeling can be used, which requires a highly qualified researcher. Carrying out of laboratory and experimental researches takes a lot of time and demands big material expenses, thus the received results are applicable only to a concrete charge. A number of authors give formulas for calculating the equivalent thermal conductivity of the strip coil. However, the practical use of such formulas is difficult due to the presence of difficult to determine parameters: the degree of the strip layers contact, thermal conductivity of different layers of strip and gas gaps between them, heat transfer coefficients by radiation in the gaps between layers. In this case, different formulas for calculating the equivalent thermal conductivity give signifi cantly different results. In the present work, for 20 steel strip coils with height, inner and outer diameters, respectively, 1; 0.4–0.966 m; with a strip thickness of 0.001; 0.003; 0.006 m, the number of layers per side 17; 25 and 50, for the coefficients of strip coil filling 0.70; 0.75; 0.80; 0.85; 0.90; 0.95; 0.97; 0.99, 0.999, the degrees of the strip layers contact 2.8–3.0% and different heated media (air, nitrogen, hydrogen), the reduced thermal conductivity coefficients were calculated according to various formulas using the MathConnex mathematical package (part of MathCadPro). On the basis of the conducted researches the formula for calculation of equivalent thermal conductivity of strip coils is chosen. The results of the calculation are in good agreement with the literature data, it can be used to calculate temperature fields and thermophysical parameters in layered metal loads, as well as to calculate their heating time and furnace performance.

Detection of L-band electron paramagnetic resonance in the DPPH molecule using impedance measurements

(a) Schematic diagram of our experimental set up. (b) Resistance and reactance of the DPPH molecule for 2 GHz current in the strip coil.

Cooling Profile Analysis of Hot Strip Coil Using Finite Volume Method

To get the low temperature transformation product of austenite, study of cooling behavior of coil is essential. Temperature distribution profile of the hot strip coil has been determined by using finite volume method (FVM) vis-à-vis finite difference method (FDM). It has been demonstrated that FVM offer greater computational reliability in estimation of contact pressure distribution and hence the temperature distribution for curved and irregular profiles, owing to the flexibility in selection of grid geometry and discrete point position, Moreover, use of finite volume concept allows enforcing the conservation of mass, momentum and energy, leading to enhanced accuracy of prediction.

Numerical Simulation of Hot Rolled Coil Temperature Field in Hot Coil Box

The heat transfer model was developed and the heat transfer of the strip coil stay in the hot coil box was analyzed. The temperature distribution of the strip coil was investigated use the model. The measured results are in good agreement with the calculated ones, has a guiding significance to further improve the technology.