New methods to cope with temperature elevations in heated segments of flat plates cooled by boundary layer flow

This paper documents two reliable methods to cope with the rising temperature in an array of heated segments with a known overall heat load and exposed to forced convective boundary layer flow. Minimization of the hot spots (peak temperatures) in the array of heated segments constitutes the primary goal that sets the platform to develop the methods. The two proposed methods consist of: 1) Designing an array of unequal heaters so that each heater has a different size and generates heat at different rates, and 2) Distancing the unequal heaters from each other using an insulated spacing. Multi-scale design based on constructal theory is applied to estimate the optimal insulated spacing, heaters size and heat generation rates, such that the minimum hot spots temperature is achieved when subject to space constraint and fixed overall heat load. It is demonstrated that the two methods can considerably reduce the hot spot temperatures and consequently, both can be utilized with confidence in industry to achieve optimized heat transfer.

Organization of Mounting Division by Use of Material Flow Minimization

Paper is oriented to the solution of mounting device for knitting machines with nested workplace organization. The proposed solution is related to the transition from the nested organization to the effective circular workplace organization which improves the work environment and also increases the number of final products.

Experimental Investigation and Computational Evaluation of Contoured Endwall and Leading Edge Fillet Configurations in a Turbine NGV

Secondary flow minimization is a crucial problem in a turbine passage. In the present paper, three different ways are employed to reduce the secondary flow related total pressure loss. These are nonaxisymmetric endwall contouring, leading edge (LE) fillet, and the combination of these two approaches. Experimental investigation and computational assessment are applied for the performance calculations. The experiments are carried out in an annular Axial Flow Turbine Research Facility (AFTRF) having a diameter of 91.66cm. For the experimental measurement comparison, a reference Flat Insert is installed in the nozzle guide vane (NGV) passage. It has a constant thickness with cylindrical surface and is manufactured by stereolithography (SLA) method. Also, Flat Insert has a backward facing step at the NGV exit, and the effect of this step is analyzed computationally. Four different LE fillets are designed, and they are attached to both cylindrical Flat Insert and the contoured endwall. Total pressure measurements are taken at rotor inlet plane with Kiel probe. The probe traversing is completed with one vane pitch and from 8% to 38% span. For one of the designs, area-averaged loss is reduced by 15.06%. The simulation estimated this reduction as 6.95%. Computational evaluation is also performed at the NGV exit plane. The most effective design reduced the mass-averaged loss by 1.84% on the whole passage. The computational study did not include the rim seal flow between the vane and rotor domain and also rotor simulation was absent. The difference between the measurements and the simulation comes from these two important effects.

Pole assignment with minimum eigenvalue differential sensitivity

This paper introduces a set of mathematical formulae for calculating the eigenvalue differential sensitivities of the closed-loop state matrix with respect to the open-loop state matrix, input matrix and state feedback matrix. It provides a computational procedure for a robust pole assignment problem. The algorithm is based on a gradient flow minimization of a differentiate objective function which measures the sensitivity for all closed-loop poles. Two numerical examples are employed to illustrate the technique. Comparisons to other existing methods are made as well.