A test rig has been assembled to investigate the thermodynamic and hyd
raulic performance of a cylindrical graphite block heat exchanger cons
isting of three graphite blocks and a steel shell. The flow pattern in
the heat exchanger was triple cross-flow on the shell-side (service s
ide) with one pass per block and a single pass on the tube-side (proce
ss side). Overall heat transfer coefficients and pressure drops have b
een measured for a range of operating conditions. Shell-side leakage f
lows were significant, with values up to 19% with water and 38% with a
heat transfer oil. Corresponding increases in the overall heat transf
er coefficient without leakage flow were 8 and 21%, respectively. The
mean difference between the theoretical and experimental overall hear
transfer coefficients for the runs with leakage flow does not exceed 6
% with water as the shell-side liquid. With oil the error does not exc
eed 8%, Pressure drop models were developed for both the shell-side an
d tube-side of the heat exchanger. The tube-side model predicted the p
ressure drop with a mean error of 5%. Errors within 20% can be expecte
d for the shell-side pressure drop model. The pressure drop on the she
ll-side depends on a number of different losses and it is therefore di
fficult to be modelled accurately. (C) 1997 Elsevier Science S.A.