  Blockchain systems are challenged by the so-called Trilemma tradeoff:
decentralization, scalability and security. Infrastructure and node
configuration, choice of the Consensus Protocol and complexity of the
application transactions are cited amongst the factors that affect the
tradeoffs balance. Given that Blockchains are complex, dynamic dynamic systems,
a dynamic approach to their management and reconfiguration at runtime is deemed
necessary to reflect the changes in the state of the infrastructure and
application. This paper introduces the utilisation of Digital Twins for this
purpose. The novel contribution of the paper is design of a framework and
conceptual architecture of a Digital Twin that can assist in maintaining the
Trilemma tradeoffs of time critical systems. The proposed Digital Twin is
illustrated via an innovative approach to dynamic selection of Consensus
Protocols. Simulations results show that the proposed framework can effectively
support the dynamic adaptation and management of the Blockchain
