Transverse pressure, flow/viscosity

In these equations x and y denote independent spatial coordinates T, the temperature Tib, the mass fraction of the species p, the pressure u and v the tangential and the transverse components of the velocity, respectively p, the mass density Wk, the molecular weight of the species W, the mean molecular weight of the mixture R, the universal gas constant A, the thermal conductivity of the mixture Cp, the constant pressure heat capacity of the mixture Cp, the constant pressure heat capacity of the species Wk, the molar rate of production of the k species per unit volume hk, the speciflc enthalpy of the species p the viscosity of the mixture and the diffusion velocity of the A species in the y direction. The free stream tangential and transverse velocities at the edge of the boundaiy layer are given by = ax and Vg = —ay, respectively, where a is the strain rate. The strain rate is a measure of the stretch in the flame due to the imposed flow. The form of the chemical production rates and the diffusion velocities can be found in (7-8). 

Tubular-Blown Film Process. This process is more flexible with regard to the permissible polymer viscosity mismatch, control of film orientation balance in the transverse and machine directions through blow-up ratio, and easy randomization of film-thickness variations. Production rates are limited by flow rates per circumferential length of die (pressure drop) and cooling rates (heat transfer). 

A Newtonian fluid, of viscosity flows through a slit-like channel of narrow rectangular section, driven by a pressure drop per unit length AP/AL. The channel is of depth h and width (transverse to the flow) w, where w> h. 

A thorough study of the effect of viscosity ratio (LCP to TP) was carried out by Fekete et alP Although some authors have asserted that a viscosity ratio of less than one (LCP less viscous than TP at the processing condition) would be optimal, this was not borne out in this study. Of course processing conditions is a broad term, which includes temperature, pressure, shear rate and possibly elongation rate as well. This paper compared flow-direction and transverse strength for a variety of TPs and LCP contents, and concluded with this rule of thumb The results of the experiments revealed... 

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