fan the fire vs work up

fan the fire

verb
  • Synonym of fan the flames 

work up

verb
  • To raise; to excite; to stir up. 

  • To give (a patient) a general medical examination to assess health and fitness. 

  • To develop. 

How often have the words fan the fire and work up occurred in a corpus of books? (source: Google Ngram Viewer )