Tandem Blades Research Articles

Numerical Investigation of Tandem Airfoils for Subsonic Axial-Flow Compressor Blades

The tandem airfoil has potential to do more work as a compressor blade than a single airfoil without incurring significantly higher losses. Although tandem blades are sometimes employed as stators, they have not been used in any known commercial rotors. While the long-term goal for this program is development of a commercially viable tandem rotor, this paper discusses tandem airfoils in subsonic, shock-free rectilinear cascade flow. Existing literature data on tandem airfoils in rectilinear cascades have been compiled and presented in a Lieblein loss versus loading correlation. Large scatter in the data gave motivation to conduct an extensive 2D computational fluid dynamics (CFD) study evaluating the overall performance as a function of the relative positions of the forward and aft airfoils. CFD results were consistent with trends in the open literature, both of which indicate that a properly designed tandem airfoil can outperform a comparable single airfoil on and off design. The general agreement of the CFD and literature data serves as a validation for the computational approach.

小型・高推力エアーターボラムエンジン

The Air Turbo Ramjet (ATR) is a combined cycle engine which performs like a turbojet engine at subsonic speeds and a ramjet at supersonic speeds and therefore the ATR is an attractive propulsion system for the wide operation range (e.g. Mach 0 to Mach 4). The ATR can provide a higher specific impulse than a solid fuel rocket engine and a higher thrust per frontal area than a turbojet engine. The major ATR components are the inlet, fan (compressor), turbine, gas generator, combustor and exhaust nozzle. In the ATR, the turbine drive gas is generated by a decomposed liquid or solid fuel gas generator. In order to carry heavier payloads and to attain shorter flight time, the compact and high thrust engine is required. In this study, the ram combustor with the double-staged flameholders and the fan with tandem blade were introduced to shorten the engine length and to increase the fan pressure ratio, respectively. Furthermore, the engine testing was carried out on sea level static condition to confirm the engine component integration technologies for the ATR propulsion system.

Skin Friction following BLADE manipulation in a turbulent pipe flow

This study attempts to analyze the measured wall shear stress distribution downstream of single and tandem BLADEs in fully developed pipe flow. Previous works have indicated the adverse effect of overall drag increase with the single BLADE in both channel and pipe flows, and an even larger drag increase with the tandem BLADES. This is contrary to that observed for external boundary layer flow. Extensive comparisons are then made to the wall shear stress distribution following BLADEs in boundary layer flow, leading to the conclusion of little or no potential in the application of BLADEs alone to pipe flow.

Fundamental studies of a tandem-bladed impeller of a centrifugal pump and the pump performance in liquid/gas two-phase flow.

It is known that a head breakdown of centrifugal pumps in a two-phase flow occurs at a gas/liquid ratio less than ten percent, due to gas accumulations in the impeller. If these accumulations could be evacuated by use of an impeller with multiple tandem blades, two-phase flow pumps might be operated at a higher gas/liquid ratio. Tests to examine the effects of a tandem-bladed impeller on the pump performance in single-phase and two-phase water/ air flows are described. Experimental results in comparison with results of an unsplit impeller thow that there is no difference of the pump performance in a single-phase flow between both impellers, and a two-phase head degradation in a flow region with elongated bubbles is improved at large water flow rates.

Optimization of the Arrangement of the Front and Rear Blade Rows of a Tandem Blade Cascade

Optimization of the Arrangement of the Front and Rear Blade Rows of a Tandem Blade Cascade

Experimental Investigation of Tandem Blade Cascades with Double-Circular ARC Profiles

Article Experimental Investigation of Tandem Blade Cascades with Double-Circular ARC Profiles was published on December 1, 1988 in the journal International Journal of Turbo & Jet-Engines (volume 5, issue 1-4).

Matrix Solution of Compressible Flow on S1 Surface Through a Turbomachine Blade Row With Splitter Vanes or Tandem Blades

The basic aerothermodynamic equations of turbomachine flow expressed with respect to nonorthogonal curvilinear coordinates and corresponding nonorthogonal velocity components are used to solve the compressible flow S1 surface in a turbomachine blade row with splitter vanes or tandem blades. The equation of stream function is solved by matrix technique, and the mass flow ratio and outlet flow angle are determined by applying the Kutta-Joukowsky condition to the trailing edges of the main blade and the splitter vane. Typical examples are given to illustrate the effectiveness of the present method.

Studies on Centrifugal Pump with Tandem Blade Rows

Studies on Centrifugal Pump with Tandem Blade Rows

Studies on Centrifugal Pump with Tandem Blade Rows

Studies on Centrifugal Pump with Tandem Blade Rows

Some Experimental Results of Two Concepts Designed to Increase Turbine Blade Loading

A number of advanced blade concepts to efficiently increase turbine blade loading are being experimentally investigated. Tests made with a single-stage turbine rig have shown two of the advanced blade designs (i.e., the tandem blade and jet-flap blade) to be potentially promising. The design of these two blades and a base plain blade, together with a comparison of the test results, are presented. All three blades were designed to the same velocity diagrams. The design diagrams are based on free-vortex flow and have a significant amount of flow deceleration across the rotor hub. Test results of the three rotor configurations, obtained with the same stator assembly, are presented. The results include turbine airflow, efficiency, and reaction characteristics along with rotor exit surveys.

Paper 6: Experimental Investigations of Tandem Axial Compressors

The overall performance of the blower is first presented for a series of values of blade stagger and ‘flap angle’ of the rotor row. The influence of gap is shown up by comparison amongst these results. Experiments were then carried out in which the gap was partially closed, and it is shown that the gap is least effective near the root section. These results were confirmed by inter-row traversing. Comparison of the tandem blade row with a single row of the same overall aspect ratio is presented and the improvements due to the tandem row are assessed.