1. FEASIBILITY ANALYS OF AN MHD INDUCTIVE GENERATOR COUPLED WITH A THERMO - ACOUSTIC ENERGY CONVERSION SYSTEM S. Carcangiu 1, R. Forcinetti 1, A. Montisci 1 1 Department of Electrical and Electronic Engineering, University of Cagliari, Sardinia, Italy ABSTRACT This work fits in the feasibility analysis of a Magneto-Hydrodynamic (MHD) inductive generator, coupled with a Thermo Acoustic (TA) energy conversion system. The MHD and TA processes have the great advantage to convert energy without mechanical moving components. In this work, first the design criteria are given, then the order of magnitude of the obtained parameters is used to model the system by using the finite element method (FEM) to confirm the theoretical results. The conceptual idea and the FEM model are described. Energy Conversion process Design Parameters & Results This work is supported by ……. Schematic view of the ionized MHD-TA generator  The charge carriers are created by means of an electrical discharge and then separated by an external, high voltage, electrostatic field applied to two copper sleeve capacitor plates.  Once the equilibrium is reached, if the gas inside the duct gets to vibrate by the TA phenomena, the charge carriers give rise to an alternating electric current; this induces an electromotive force in the toroidal coils wrapped around the duct and then a current into the load.  The TA phenomena occur when a great gradient of temperature is present in the longitudinal direction of a duct containing a gas. In order to obtain said gradient we need a heat source and a stack inside the duct with a large surface.  The TA effect allows transforming the thermal energy into vibration energy. The gradient of temperature affects the flow rate of energy, while the frequency is determined by the length of the duct.  Need of very high external Magnetic Field  High temperatures are needed to ionize gas  Seeding Recovery  Deterioration of electrodes  Need for flowing working fluid Drawbacks of classical MHD generators  No external Magnetic Field  No Superconducting Coils  High Performance at Low Temperatures  No seeding  Quasi - Static working fluid Advantages of the proposed device Numerical simulations Thermo – acoustic analysis Design Parameters P 0 = 200 W R = 12 cm R D = 7 cm  = 15 C/m 3 V 0 = 30 m/s n = 10 tr S = 3 10 -3 m 2   10 3 rad/s  f =  0  5  10 4 H/m  = 0.5 mm  = 1000 Results i 0 = 1.6 A V coil = 177 V I 0 = 11.28 A U 0 = 17.72 V R e = 200  C = 0.8  F  kV |B| = 0.94 T Electrostatic analysis Theoretical development and demonstrative facility sizing A first study has been done in order to propose a simplified theory about the performances of the MHD induction ionized gas generator coupled with the thermo acoustic engine. The order of magnitude of design parameters obtained has been used to modeling and simulate the system. This study starts from the equation of Ampere and the equation of the circuit Electric circuit scheme Conclusions and future works These are encouraging preliminary results. For the future we have reduce the simplificative hypothesis and then to develop a FEM model of the coupled problems (both thermo-acustic and electrostatic). Reminding the Displacement current that is due to the existence of significant gradients of the electric field. It will be also very interesting to study the influence of the Displacement current on the value of the inducted current in presence of acoustic vibration. 1.Avoid the core saturation (low B) 2.Work at low ionization levels (low I) Charge density and velocity amplitude have in general strict limits, then we can foresee that the size of the device will be the key parameter in order to fulfill the requirements. Objectives: Velocity distribution (Rd=7cm; f=1000 Hz) Optimal distribution of the electrical potential along the duct (Vapplied=1.63MV)