(1) the matrix viscosity and thermal conductivity. For liquid substances, within a certain temperature range, the better the fluidity, the internal friction of a liquid substance, the smaller, the better the heat transfer, the thermal conductivity will be. Generally small drug volume freezing point of the oil phase of emulsion explosives between 42--45 degrees phase solidification temperature range of oil in this low point, viscosity is low, the thermal conductivity of the large. Low freezing point as the oil phase, the explosives storage period is short.
(2) thermal conductivity of metal pipe materials. Different metals with different coefficients of thermal conductivity, good electrical conductivity of metal materials, thermal resistance or.
(3) the metal pipe surface finish factor. Matrix viscosity 450Pa.s, will produce a strong adhesion when in contact with the wall at room temperature. When the metal surface roughness, on the surface layer of the matrix will be adhered, the rougher the surface of the wall, the thicker the adhesive layer, then this layer of adhesive material is cooled continuously, the stronger adhesion, thermal resistance is this layer of adhesive material and the thermal resistance of the metal wall and led to the decline in the heat transfer coefficient.
(4) The heat transfer area S of factors. From the thermal conductivity (heat safety rules) formula. Matrix and metal wall of the contact area S is larger, the better the cooling effect.
(5) cooling water temperature factors. Emulsion explosive oil phase component generally wax content, since the explosive is W / O type, in contact with the metal wall is the continuous phase. Apparent thermal conductivity equation, Q values when △ T is large, the heat exchange is large. After testing, the freezing point of the oil phase when the temperature T at 46 degrees, or less than 40 degrees, with the decline in the cooling water temperature, the substrate temperature T1 greater the difference between the cooling water temperature T2 of the cooling water temperature T2, i.e. the greater △ T adhered to the metal wall of the thicker substrates, such as promoting low pressure matrix, the matrix on the wall does not move, resulting in increased thermal resistance. Only when the water temperature is above 40 degrees, △ T larger the better cooling effect.
(6) cooling water tube spacing factor. When two tube spacing a far, the substrate temperature of the substrate between the center and the tube wall temperature on the difference between the two tubes is large, otherwise small; separation a large, matrix motion resistance decreased, the resistance increased and vice versa. Take into account not only the size of a pitch T1 and T2, the temperature difference between the factors should be considered coolant temperature, oil temperature phase condensation point, the matrix motion screw the day pressure and other factors.
(7) film strength factor. When △ T is small, the required driving force behind the movement matrix is small, the pressure on the substrate is low, whereas the pressure on the matrix is high. To obtain good heat transfer effect, should try to increase the temperature difference between T1 and T2, it should increase the external pressure matrix. Only film strength to withstand this pressure, in order to achieve the desired cooling effect, when the pressure exceeds the film strength to withstand the pressure, breaking phenomenon occurs.
Safety factor (8) of the cooling system. The cooler matrix thrust movement by screw moves, the longer the cooler, cooling the better, the greater the drag screw, friction matrix with the screw shaft, a rubber sleeve in the pump the greater the resistance, the security risk is also high. Therefore, the length of the cooler should be set according to the date of the security pressure screw, generally screw conveyor emulsion explosives safety pressure 1.0MPa a day or less.