Modeling of a Hot Gas Bypass Test Block for Centrifugal Compressors (original) (raw)
Related papers
Thermodynamic Analysis of Inlet Air Cooling System for a Centrifugal Compressor
2018
In large air compressor installations consisting of multiple compressors operating continuously, even a small reduction in the inlet air temperature can improve the plant efficiency. Exergy efficiency is more rational than energy efficiency, and exergy analysis is more helpful than energy analysis for locating and evaluating available energy-saving potentials, identifying opportunities for improvements in system design, and establishing cost-effective system maintenance programs. When exergy analysis is performed on a system, thermodynamic imperfections can be quantified as exergy destruction, which represent losses in energy quality. In the present study, a thermodynamic analysis is made on the inlet air cooling system employed in a centrifugal compressor. Exergy input rate, exergy output rate, exergy loss rate, exergy destruction rate, and exergy efficiency were calculated with five different dead state temperatures and five different dead state relative humidities. Sustainability...
This is the second part of a study conducted to model the aerothermodynamic impact of suction parameters and gas properties on a multi-stage centrifugal compressor's performance. A new iterative method has been developed in the first part to derive the equivalent performance at various operating conditions. This approach has been validated to predict the compressor map at different suction pressures and temperatures using the design characteristics as reference values. A further case is included in this paper in order to emphasize the validity of the developed approach to obtain the performance characteristics at various gas compositions. The provided example shows that the performance parameters at different gas mixtures can be predicted to within ±1.34%. Furthermore, the conducted optimization in this paper reveals that the proposed method can be applied for the compressor design evaluation corresponding to the expected variation in suction conditions. Moreover, the examined case study demonstrates the effect of gas properties' variation on the operating point and aerodynamic stability of the entire compression system. In order to achieve that, a simple approach has been established to assess the contribution of gas properties' variation to the inefficient and unstable compressor performance based on the available operational data.
Nigerian Journal of Technology, 2021
In today’s world where fuel prices have increased drastically and there are great concerns about environmental issues, there is the need to properly match centrifugal compressors to their Gas Turbine (GT) drivers, so as to achieve an efficient overall package, lower turbine fuel consumption, longer time between overhauls, and most importantly, package operational flexibility in meeting alternate process conditions. This study highlights the influence of operating and environmental conditions on the overall performance of the gas turbine compressor set. GasTurb and CMap simulation softwares were employed to model and simulate the performances of the GT and centrifugal compressors respectively. The outcome of the performance plots show that at a design inlet flow volume of 15928 cubic meters per hour, the compressor required power from the gas turbine drive to transport RaNatGas is approximately 7450kW as against 7065kW and 6500kW for MaNatGas and LaNatGas mixtures respectively. Te...
Analysis of centrifugal compressor testing capabilities
IMK-14 - Istrazivanje i razvoj, 2021
The work shows examining of the centrifugal compressor for which there are no technical conditions by which the compressor manufacturer defines the form and important characteristics of the measuring installation. In the absence of the necessary data, a table for testing of centrifugal compressors was designed, where the pipeline measures and other details are freely defined in accordance with the available possibilities.
Numerical study of the heat transfer effect on a centrifugal compressor performance
This paper presents a study of the heat transfer influence on the centrifugal compressor performance. The compressor studied in this paper is based on the scale-up of a turbocharger compressor equipped with a shroudless impeller. To account for the heat transfer effect, a conjugate heat transfer analysis is performed with computational fluid dynamics techniques. The heat transfer phenomena not only externally but also internally are investigated at the design point. The grids adopted in the study are verified at the baseline, with an excellent agreement found between numerical simulations and measurements. The results provide an insight into the dependence of the heat transfer influences on the heat flux paths. The path of the external heat flux passing through the impeller shaft is found to have a great impact on the compressor performance. The study of internal heat transfer shows that the shroud surface dominates the internal heat transfer effect on the efficiency loss. Furthermore, the heat transfer influence is also investigated on the compressor performance at other operating points. The results imply a positive potential margin for the improvement of compressor efficiency by means of heat transfer control.
Issues of gas dynamic characteristics modeling: a study on a centrifugal compressor model stage
E3S Web of Conferences, 2019
The paper presents the results of CFD-calculations of a centrifugal compressor stage with a high-pressure 3D impeller and a vaneless diffuser. The stage was designed by Prof. A. M. Simonov in the Problem Laboratory of Compressor LPI according to the following design parameters: flow rate coefficient 0.080, loading factor 0.74, and the relative Mach number 0.78. Two design grids were used: 2.4 and 4.4 million cells for the sector with one blade. The entire stage was calculated with a sparser grid. Special “Stage” interface conditions are used to interface the gas-dynamic parameters at the boundary regions. The SST turbulence model was used in the calculations. The results of efficiency characteristics and work coefficient comparison showed the following: in design flow rate all three variants of the calculation overstate the loading factor by 14.3%; the calculated characteristics of polytrophic work coefficient in the staging of 360 degrees are closest to the experimental characteris...
Design and Operation of a Centrifugal Compressor in a High Temperature Heat Pump
2019
This article presents the design, simulation and operation of a single stage 800 kWe centrifugal compressor operating with HFO R1234ze(E). The compressor is integrated in a high temperature heat pump that converts heat from saturated steam at 48°C into 3.5 MWth of heat at 75°C for a district heating network. The compressor specifications require a high-pressure ratio (above 3), a high isentropic efficiency and a wide operation range. The compressor design process is discussed in detail, starting from the preliminary optimization based on the mean-line model and then focusing on the aerodynamic design of each component of the compressor. In particular, the design of the inlet guide vanes (IGV), of the impeller, of the vaneless and vaned diffusers, and finally of the exhaust volute are presented in detail. Nominal and off design performances are then assessed by means of computational fluid dynamics (CFD), performed by applying the commercial solver ANSYS CFX. The simulations are base...
Modeling and Testing of a Two-Stage Rotary Compressor
2008
While previous research studies have analyzed the compression process of single-stage rotary compressors, little information is available on two-stage rotary compressors. However, two-stage compressors provide opportunities for energy savings through modifications such as intercooling and economizing. This paper presents a computer model of a hermetic two-stage rotary compressor that was developed to provide design engineers with the means to optimize the compressor design.
Predictions of Heat Transfer in Compressor Cylinders
ABSTRA CT Two numerical models are used to investigat e the instantane ous heat transfer between the cylinder walls and gas in a reciprocat ing compresso r. One model uses simple mass and energy balances to predict the bulk thermody namic properties of the gas in the cylinder. Heat transfer between the cylinder walls and the gas is calculated with a widely used correlatio n for the heat transfer coeffiecien t. The other model solves the unsteady continuity , momentum , and energy equations for the gas in the cylinder using a finite-diffe rence technique. No heat transfer coefficient is needed in this model. Results from the finite-diffe rence model agree quite well with the published results from experimen ts and similar computati ons for compresso rs and non-firing reciprocat ing engines. The instantane ous heat transfer predicted by the simple model is an order of magnitude less than that predicted by the finite-diffe rence model.
Compressor intake-air cooling in gas turbine plants
Energy, 2004
The generated power and efficiency of gas turbine plants depend on the temperature of the inlet air. At high ambient temperatures, a power loss of more than 20%, combined with a significant increase in specific fuel consumption, compared to ISO standard conditions (15 v C), can be observed. The purpose of this work is to present a computer simulation of the integration of an innovative technology for reducing the intake-air temperature in gas turbine plants. Following a description of the air-cooling system, simulation results for two test cases are presented: a simple cycle gas turbine and a combined cycle plant. First, the effect of ambient air temperature variation on the power output and efficiency is presented for both cases. Next, the results from the integration of an evaporative cooler and of the air-cooling system under consideration are presented and discussed, demonstrating the gain in power output and efficiency that can be achieved. #