Redesign The Electricity System of PT Barata Indonesia To Reduce Annual Power Loss

PT Barata is one of Indonesia’s leading turbine component manufacturers, requiring a large amount of electricity for production. Along with the increase in production and factory expansion, the need for electricity continues to increase so that it continues to add power to reach 3780 KVA. One of the weaknesses of the electric power system at PT Barata is using six (6) 20kV/400 V, 630 kVA transformer units. This system produces a no-load or core loss of 8150 Watts. In one year, the power loss reached 71.394 kWh at the cost of IDR 118,514,040.00. Power loss is permanent and lasts all the time during the use of the Transformer. This article aims to redesign the electrical system at PT Barata using a single 4000 kVA transformer. The redesign of the electric power system at PT Barata was carried out by 1. Observing and measuring the electric power system at PT Barata, 2. calculating the resulting losses, 3. conducting studies and designs, 4 comparing the ratio of the total power loss of the electric power system currently with a new design, 5. Propose a redesign to management for implementation. Calculation and analysis of the new design with a 4000 kVA transformer obtained a core loss of 4450 Watt at the cost of Rp. 64,905.030.00, resulting in a savings of IDR. 53,965,980.00 per year. The new design will save 45% in operating costs compared to the previous six transformer units.

CONVECTION IN SCALED TURBINE INTERNAL COOLING PASSAGES WITH ADDITIVE MANUFACTURING ROUGHNESS

Additive manufacturing processes, such as direct metal laser sintering (DMLS), enable creation of novel turbine cooling internal passages and systems. However, the DMLS method produces a significant and unique surface roughness. Previous work in scaled passages analyzed pressure losses and friction factors associated with the rough surfaces, as well as investigated the velocity profiles and turbulent flow characteristics within the passage. In this study, the heat transfer characteristics of scaled additively manufactured surfaces were measured using infrared (IR) thermography. Roughness panels were CNC machined from plates of aluminum 6061 to create near isothermal roughness elements when heated. Fluid resistance differences between the aluminum roughness panels and roughness panels constructed from ABS plastic using the same roughness patterns from McClain et al. (2020) were investigated. Finally, the overall thermal performance enhancements and friction losses were assessed through calculation of surface averaged “global thermal performance” ratios. The global thermal performance characterizations indicate results in-line with those found for traditional commercial roughness and slightly below traditional internal passage convection enhancement methods such as swirl chambers, dimples, and ribs. The passages investigated in this study do not include compressibility effects or the long-wavelength artifacts and channel geometric deviations observed by Wildgoose et al. (2020). However, the results of this study indicate that, based on the roughness augmentation alone, artificial convective cooling enhancers such as turbulators or dimples may still be required for additively manufactured turbine component cooling.

Numerical Simulation of Flow across a Radial Turbine for Prediction of Shaft Power for Driving Automobile Air Conditioners

The exhaust gas spouting from the exhaust manifold into the radial inflow turbine coupled to an exhaust pipe of a 2.5L petrol engine has been computationally simulated in order to ascertain the extent of exhaust energy recoverability for driving the vehicle auxiliaries, using Autodesk CFD. In order to determine the amount of power available at the turbine shaft at varying engine speeds, properties of the flow and fluid spouting into the turbine from the engine and out of the turbine from the volute outlet were examined by applying the SST k-? turbulence model and advanced Petrov-Galerkin's advection scheme. For the test engine used with the operating range of 2000-6000rpm, at engine speeds up to 3000rpm, the available power was about 0.3kW. At 4000rpm, about 2.8kW of power is available at the turbine shaft, increasing to 7.7kW at 5000rpm and 43.6kW at 6000rpm. Curve-fitting shows that at 5500rpm, as much as 15kW reversible power can be extracted from a shaft coupled to the turbocharger turbine. With an electrically-assisted turbine component of the turbocharger used, the compressor of vapour compression refrigeration system of the vehicle will be efficiently driven at all engine speeds while exhaust energy recovery is achieved.

New Unloading Possibilities of Gas Turbine Combined Cycle Power Generating Units

The determining factor for the efficient operation of electrical systems is their stability. To ensure stability, it is important to establish links between neighboring electrical systems, enhance the capacity of overloading and unloading power plants, improving the flexibility of power plants, etc. For electrical systems with high autonomy, it is also important to solve the problems of power control by the installations of the system itself, including the combined cycle power units, the main purpose of which is to cover the base load of the grid. The studies carried out by the authors of the article have shown that the tasks of regulating the load of electric power systems can be solved by using power units of a gas turbine combined cycle. In order to achieve this, it is required to identify and realize deep unloading capabilities of such power generating units. In standard conditions the combined cycle power generating units are utilized for covering base loads, and their participation in a daily regulation of the grid load is not considered. However, the concept of the combined power control method suggested by the authors of this article involves combination of quantitative and qualitative regulation methods of the gas turbine component which significantly expands the unloading range of such power generating units and increases their engagement in regulating the power system loads.

Dependence of LPBF Surface Roughness on Laser Incidence Angle and Component Build Orientation

Laser Powder Bed Fusion (LPBF) of metallic components is unlocking new design options for high efficiency gas turbine component designs not possible by conventional manufacturing technologies. Surface roughness is a key characteristic of LPBF components that impacts heat transfer correlations and crack initiation from co-located surface defects — both are critical for gas turbine component durability and performance. However, even for a single material, there is an increasing diversity in laser machines (single vs multi-laser), layer thicknesses (∼20–80 microns) and orientations to the build plate (upskin, vertical and downskin) that result in significant variability in surface roughness. This study systematically compares the surface roughness across the above-mentioned variables to further develop a repeatable correlation of surface roughness to the angle between the substrate normal and laser incidence direction. This presented data will be discussed in detail, to show potential applicability of this process signature curve across materials, machines, and substrate orientations. Future steps to a rapid process qualification standard for surface roughness, across Siemens Energy’s global manufacturing footprint will also be discussed.

Experimental and Computational Investigation of Integrated Internal and Film Cooling Designs Incorporating a Thermal Barrier Coating

Few studies in the open literature have studied the effect of thermal barrier coatings when used in combination with shaped hole film cooling and enhanced internal cooling techniques. The current study presents RANS conjugate heat transfer simulations that identify trends in cooling design performance as well as experimental measurements of overall effectiveness using a flat-plate matched-Biot number model with a simulated TBC layer of 0.42D thickness, where D is the film cooling hole diameter. Coolant is fed to the film cooling holes in a co-flow configuration, and the results of both smooth and rib-turbulated channels are compared. At a constant coolant flow rate, enhanced internal cooling was found to provide a 44% increase in spatially-averaged overall effectiveness, ϕ ̿ , without a TBC. The results show that the addition of a TBC can raise ϕ ̿ on a film-cooled component surface by 47%. The optimum velocity ratio was found to decrease with the addition of enhanced cooling techniques and a TBC as the film provided minimal benefit at the expense of reduced internal cooling. While the computational results closely identified trends in overall system performance without a TBC, the model over-predicted effectiveness on the metal-TBC interface. The results of this study will inform turbine component design as material science advances increase the reliability of TBC.

Convection in Scaled Turbine Internal Cooling Passages With Additive Manufacturing Roughness

Additive manufacturing processes, such as direct metal laser sintering (DMLS), enable creation of novel turbine cooling internal passages and systems. However, the DMLS method produces a significant and unique surface roughness. Previous work in scaled passages analyzed pressure losses and friction factors associated with the rough surfaces, as well as investigated the velocity profiles and turbulent flow characteristics within the passage. In this study, the heat transfer characteristics of scaled additively manufactured surfaces were measured using infrared (IR) thermography. Roughness panels were CNC machined from plates of aluminum 6061 to create near isothermal roughness elements when heated. Fluid resistance differences between the aluminum roughness panels and roughness panels constructed from ABS plastic using the same roughness patterns from McClain et al. (2020) were investigated. Finally, the overall thermal performance enhancements and friction losses were assessed through calculation of surface averaged “global thermal performance” ratios. The global thermal performance characterizations indicate results in-line with those found for traditional commercial roughness and slightly below traditional internal passage convection enhancement methods such as swirl chambers, dimples, and ribs. The passages investigated in this study do not include compressibility effects or the long-wavelength artifacts and channel geometric deviations observed by Wildgoose et al. (2020). However, the results of this study indicate that, based on the roughness augmentation alone, artificial convective cooling enhancers such as turbulators or dimples may still be required for additively manufactured turbine component cooling.